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

tests/compiler/dart2js/cps_ir/input/constructor_12.dart

Index: tests/compiler/dart2js/cps_ir/input/constructor_12.dart
diff --git a/tests/compiler/dart2js/cps_ir/input/constructor_12.dart b/tests/compiler/dart2js/cps_ir/input/constructor_12.dart
new file mode 100644
index 0000000000000000000000000000000000000000..efafb994f1b4552dbe5a716207e78952ad88af78
--- /dev/null
+++ b/tests/compiler/dart2js/cps_ir/input/constructor_12.dart
@@ -0,0 +1,11 @@
+class Foo {
+  factory Foo.make(x) {
+    print('Foo');
+    return new Foo.create(x);
+  }
+  var x;
+  Foo.create(this.x);
+}
+main() {
+  print(new Foo.make(5));
+}