Pull JS assignments into var initializer.

tests/compiler/dart2js/js_backend_cps_ir_constructor_test.dart

Index: tests/compiler/dart2js/js_backend_cps_ir_constructor_test.dart
diff --git a/tests/compiler/dart2js/js_backend_cps_ir_constructor_test.dart b/tests/compiler/dart2js/js_backend_cps_ir_constructor_test.dart
index e77d5cd4e1414367a40bc595ed82c57e24cb4390..59a977761c96967d3ba0ab0a3230142616e9042a 100644
--- a/tests/compiler/dart2js/js_backend_cps_ir_constructor_test.dart
+++ b/tests/compiler/dart2js/js_backend_cps_ir_constructor_test.dart
@@ -68,8 +68,7 @@ main() {
 }""",
 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;
@@ -98,8 +97,7 @@ main() {
 }""",
 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();
@@ -130,12 +128,7 @@ main() {
 """,
 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);
 }"""),
 
@@ -159,8 +152,7 @@ main() {
 """,
 r"""
 function() {
-  var v0;
-  v0 = new V.Foo();
+  var v0 = new V.Foo();
   v0.Bar$5$q$w$y$z("x", null, "w", "y", "z");
   return v0;
 }"""),
@@ -195,8 +187,7 @@ main() {
   new C<int>();
 }""", r"""
 function($T) {
-  var v0;
-  v0 = H.setRuntimeTypeInfo(new V.C(), [$T]);
+  var v0 = H.setRuntimeTypeInfo(new V.C(), [$T]);
   v0.C$0();
   return v0;
 }"""),