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

tests/compiler/dart2js/cps_ir/expected/closures_15.js

Index: tests/compiler/dart2js/cps_ir/expected/closures_15.js
diff --git a/tests/compiler/dart2js/cps_ir/expected/closures_15.js b/tests/compiler/dart2js/cps_ir/expected/closures_15.js
new file mode 100644
index 0000000000000000000000000000000000000000..46c7d38445f7459e9f8b3bc2bdb5406c605e85ee
--- /dev/null
+++ b/tests/compiler/dart2js/cps_ir/expected/closures_15.js
@@ -0,0 +1,17 @@
+// Expectation for test: 
+// class Foo {
+//   get getter {
+//     print('getter');
+//     return (x) => x;
+//   }
+// }
+// main(x) {
+//   var notTearOff = new Foo().getter;
+//   print(notTearOff(123));
+// }
+
+function(x) {
+  V.Foo$();
+  P.print("getter");
+  P.print(new V.Foo_getter_closure().call$1(123));
+}