dart2js cps: Pull SetFields into field initializer arguments.

tests/compiler/dart2js/cps_ir/expected/constructor_15.js

Index: tests/compiler/dart2js/cps_ir/expected/constructor_15.js
diff --git a/tests/compiler/dart2js/cps_ir/expected/constructor_15.js b/tests/compiler/dart2js/cps_ir/expected/constructor_15.js
new file mode 100644
index 0000000000000000000000000000000000000000..22c0973f22c24d0386533b9124845ef5f9b95b8e
--- /dev/null
+++ b/tests/compiler/dart2js/cps_ir/expected/constructor_15.js
@@ -0,0 +1,19 @@
+// Expectation for test: 
+// // Method to test: generative_constructor(A#)
+// class A {
+//   var x, y, z;
+//   A(x, y) {
+//     this.x = x;
+//     this.y = y;
+//     this.z = this.x / 2;
+//   }
+// }
+// 
+// main() {
+//   print(new A(123, 'sdf').y);
+//   try {} finally {} // Do not inline into main.
+// }
+
+function(x, y) {
+  return new V.A(x, y, x / 2);
+}