dart2js cps: Generate increment and compound operators.

tests/compiler/dart2js/js_backend_cps_ir_control_flow_test.dart

 // Copyright (c) 2014, 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.
 
 // Tests of control flow statements.
 
 library control_flow_tests;
 
 import 'js_backend_cps_ir.dart';
 
@@ skipping 135 matching lines @@
 }"""),
   const TestEntry("""
 main() {
   var list = [1,2,3,4,5,6];
   for (var x in list) {
     print(x);
   }
 }""",r"""
 function() {
   var list = [1, 2, 3, 4, 5, 6], i = 0, v0;
-  for (; i < 6; i = i + 1) {
+  for (; i < 6; ++i) {
     v0 = H.S(list[i]);
     if (typeof dartPrint == "function")
       dartPrint(v0);
     else if (typeof console == "object" && typeof console.log != "undefined")
       console.log(v0);
     else if (!(typeof window == "object")) {
       if (!(typeof print == "function"))
         throw "Unable to print message: " + String(v0);
       print(v0);
     }
   }
 }"""),
   const TestEntry("""
 main() {
   var xs = ['x', 'y', 'z'], ys = ['A', 'B', 'C'];
   var xit = xs.iterator, yit = ys.iterator;
   while (xit.moveNext() && yit.moveNext()) {
     print(xit.current);
     print(yit.current);
   }
 }""",r"""
 function() {
   var xs = ["x", "y", "z"], ys = ["A", "B", "C"], i = 0, i1 = 0, current, current1;
-  for (; i < 3; i = i + 1, i1 = i1 + 1) {
+  for (; i < 3; ++i, ++i1) {
     current = xs[i];
     if (!(i1 < 3))
       break;
     current1 = ys[i1];
     P.print(current);
     P.print(current1);
   }
 }"""),
 ];
 
 void main() {
   runTests(tests);
 }