Use more js templates in async rewrite.

tests/compiler/dart2js/async_await_js_transform_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 import "package:compiler/src/js/js.dart";
 import "package:compiler/src/js/rewrite_async.dart";
 
 import "backend_dart/dart_printer_test.dart" show PrintDiagnosticListener;
 
@@ skipping 18 matching lines @@
 
 main() {
   testTransform("""
 function(a) async {
   print(this.x); // Ensure `this` is translated in the helper function.
   await foo();
 }""", """
 function(a) {
   var __goto = 0, __completer = new Completer(), __handler = 1, __currentError, __self = this;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
           print(__self.x);
           __goto = 2;
           return thenHelper(foo(), __body, __completer);
@@ skipping 29 matching lines @@
         }
       }
     } finally {
       return 3; // Return from finally with no pending finally.
     }
     return 4;
   }""", """
 function(b) {
   var __goto = 0, __completer = new Completer(), __handler = 2, __currentError, __next, __returnValue, __helper;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       __outer1:
         switch (__goto) {
           case 0:
             // Function start
             __handler = 3;
           case 7:
@@ skipping 91 matching lines @@
   a = b++; // post- and preincrements.
   b = --b;
   c = (await foo()).a++;
   d = ++(await foo()).a;
   e = foo1()[await foo2()]--;
   f = --foo1()[await foo2()];
 }""", """
 function(c) {
   var __goto = 0, __completer = new Completer(), __handler = 1, __currentError, a, b, c, d, e, f, __temp1;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
           a = b++;
           b = --b;
           __goto = 2;
@@ skipping 36 matching lines @@
     c = await foo1() || foo3(await foo2());
     d = foo1() || foo2();
     e = foo1() && await foo2();
     f = await foo1() && foo2();
     g = await foo1() && await foo2();
     h = foo1() && foo2();
   }""", """
 function(d2) {
   var __goto = 0, __completer = new Completer(), __handler = 1, __currentError, a, b, c, d, e, f, g, h, __temp1;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
           __temp1 = foo1();
           if (__temp1) {
             // goto then
@@ skipping 116 matching lines @@
         await foo();
         break; // Break the switch
       case 2:
         foo(); // No default
     }
   }
 }""", """
 function(x, y) {
   var __goto = 0, __completer = new Completer(), __handler = 1, __currentError;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
         case 2:
           // while condition
         case 4:
@@ skipping 66 matching lines @@
       if (a) // If with no awaits in body
         break;
       else
         continue;
     } while (await foo());
   }
   """, """
 function(f) {
   var __goto = 0, __completer = new Completer(), __handler = 1, __currentError, a;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
         case 2:
           // do body
           __goto = 5;
@@ skipping 44 matching lines @@
       await foo();
       return;
     }
     print(await(foo(i)));
   } 
 }
 """, """
 function(g) {
   var __goto = 0, __completer = new Completer(), __handler = 2, __currentError, __returnValue, i, __temp1;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
           i = 0;
         case 3:
           // for condition
@@ skipping 64 matching lines @@
     x["a"] = 2; // Different assignments
     (await foo()).a = 3;
     x[await foo()] = 4;
     x[(await foo1()).a = await foo2()] = 5;
     (await foo1())[await foo2()] = await foo3(6);
   }
   """, """
 function(a, h) {
   var __goto = 0, __completer = new Completer(), __handler = 1, __currentError, x, __temp1, __temp2;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
           __temp1 = foo1();
           __goto = 2;
           return thenHelper(foo2(), __body, __completer);
@@ skipping 60 matching lines @@
       y.x = foo(error);
     } finally {
       foo(x);
     }
   }
 }
 """, """
 function(c, i) {
   var __goto = 0, __completer = new Completer(), __handler = 1, __currentError, x, y, __error1, __error2;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
           __handler = 3;
           __goto = c ? 6 : 8;
           break;
@@ skipping 89 matching lines @@
     print(await(foo(x))); // calls
     (await print)(foo(x));
     print(foo(await x));
     await (print(foo(await x)));
     print(foo(x, await y, z));
   }
   """, """
 function(x, y, j) {
   var __goto = 0, __completer = new Completer(), __handler = 1, __currentError, __temp1, __temp2, __temp3;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
           __temp1 = print;
           __goto = 2;
           return thenHelper(foo(x), __body, __completer);
@@ skipping 62 matching lines @@
       default: // defaul case
         break lab; // break to label
       }
       foo();
     }
   }
 }""", """
 function(x, y, k) {
   var __goto = 0, __completer = new Completer(), __handler = 2, __currentError, __returnValue, __temp1;
   function __body(__errorCode, __result) {
-    if (__errorCode == 1) {
+    if (__errorCode === 1) {
       __currentError = __result;
       __goto = __handler;
     }
     while (true)
       switch (__goto) {
         case 0:
           // Function start
         case 3:
           // while condition
           __goto = 5;
@@ skipping 92 matching lines @@
           // return
           return thenHelper(__returnValue, 0, __completer, null);
         case 2:
           // rethrow
           return thenHelper(__currentError, 1, __completer);
       }
   }
   return thenHelper(null, __body, __completer, null);
 }""");
 }