Pull JS assignments into var initializer.

tests/compiler/dart2js/js_backend_cps_ir_constructor_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.
 // VMOptions=-DUSE_CPS_IR=true
 
 // Tests of interceptors.
 
 library constructor_test;
 
 import 'js_backend_cps_ir.dart';
@@ skipping 50 matching lines @@
   var y;
   Sub(x, this.y) : super(x) {
     print(x);
   }
 }
 main() {
   print(new Sub(1, 2).x);
 }""",
 r"""
 function(x, y) {
-  var v0;
-  v0 = new V.Sub(y, x);
+  var v0 = new V.Sub(y, x);
   v0.Base0$0();
   v0.Sub$2(x, y);
   return v0;
 }"""),
 
   const TestEntry.forMethod('generative_constructor(Sub#)', """
 class Base0 {
   Base0() {
     print('Base0');
   }
 }
 class Base extends Base0 {
   var x;
   Base(x1) : x = (() => ++x1) {
     print(x1); // use boxed x1
   }
 }
 class Sub extends Base {
   var y;
   Sub(x, this.y) : super(x) {
     print(x);
   }
 }
 main() {
   print(new Sub(1, 2).x);
 }""",
 r"""
 function(x, y) {
-  var _box_0, v0;
-  _box_0 = {};
+  var _box_0 = {}, v0;
   _box_0._captured_x1_0 = x;
   v0 = new V.Sub(y, new V.Base_closure(_box_0));
   v0.Base0$0();
   v0.Base$1(_box_0);
   v0.Sub$2(x, y);
   return v0;
 }"""),
 
   const TestEntry.forMethod('generative_constructor(Sub#)', """
 foo(x) {
@@ skipping 10 matching lines @@
   var y2;
   var y3;
   Sub() : y2 = foo('y2'), super(), y3 = foo('y3');
 }
 main() {
   new Sub();
 }
 """,
 r"""
 function() {
-  var v0, v1, v2, v3, v4;
-  v0 = V.foo("y1");
-  v1 = V.foo("y2");
-  v2 = V.foo("x1");
-  v3 = V.foo("x3");
-  v4 = V.foo("x2");
+  var v0 = V.foo("y1"), v1 = V.foo("y2"), v2 = V.foo("x1"), v3 = V.foo("x3"), v4 = V.foo("x2");
   return new V.Sub(v0, v1, V.foo("y3"), v2, v4, v3);
 }"""),
 
 
   const TestEntry.forMethod('generative_constructor(Foo#)', """
 class Bar {
   Bar(x, {y, z: 'z', w: '_', q}) {
     print(x);
     print(y);
     print(z);
     print(w);
     print(q);
   }
 }
 class Foo extends Bar {
   Foo() : super('x', y: 'y', w: 'w');
 }
 main() {
   new Foo();
 }
 """,
 r"""
 function() {
-  var v0;
-  v0 = new V.Foo();
+  var v0 = new V.Foo();
   v0.Bar$5$q$w$y$z("x", null, "w", "y", "z");
   return v0;
 }"""),
   const TestEntry(r"""
 class C<T> {
   foo() => T;
 }
 main() {
   print(new C<int>().foo());
 }""", r"""
@@ skipping 14 matching lines @@
 }"""),
   const TestEntry.forMethod('generative_constructor(C#)', r"""
 class C<T> {
   C() { print(T); }
   foo() => print(T);
 }
 main() {
   new C<int>();
 }""", r"""
 function($T) {
-  var v0;
-  v0 = H.setRuntimeTypeInfo(new V.C(), [$T]);
+  var v0 = H.setRuntimeTypeInfo(new V.C(), [$T]);
   v0.C$0();
   return v0;
 }"""),
   const TestEntry.forMethod('generative_constructor(C#)', r"""
 class C<T> {
   var x;
   C() : x = new D<T>();
 }
 class D<T> {
   foo() => T;
 }
 main() {
   print(new C<int>().x.foo());
 }""", r"""
 function($T) {
   return H.setRuntimeTypeInfo(new V.C(V.D$($T)), [$T]);
 }"""),
 ];
 
 void main() {
   runTests(tests);
 }