cpsir unittests: move all unittests into individual files and test runners.

tests/compiler/dart2js/cps_ir/expected/constructor_4.js

Index: tests/compiler/dart2js/cps_ir/expected/constructor_4.js
diff --git a/tests/compiler/dart2js/cps_ir/expected/constructor_4.js b/tests/compiler/dart2js/cps_ir/expected/constructor_4.js
new file mode 100644
index 0000000000000000000000000000000000000000..7253134d48b56a9480fefa9458f7953d1a08bc3a
--- /dev/null
+++ b/tests/compiler/dart2js/cps_ir/expected/constructor_4.js
@@ -0,0 +1,30 @@
+// Expectation for test: 
+// 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);
+// }
+
+function() {
+  var _box_0 = {};
+  _box_0.x1 = 1;
+  P.print("Base0");
+  P.print(_box_0.x1);
+  P.print(1);
+  P.print(new V.Base_closure(_box_0));
+}