Split js_backend_cps_ir tests into multiple test units.

tests/compiler/dart2js/js_backend_cps_ir_control_flow_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+// VMOptions=-DUSE_CPS_IR=true
 
 // Tests of control flow statements.
 
 library control_flow_tests;
 
-import 'js_backend_cps_ir_test.dart';
+import 'js_backend_cps_ir.dart';
 
 const List<TestEntry> tests = const [
   const TestEntry("""
 main() {
   while (true);
 }
 """, """
 function() {
   while (true)
     ;
@@ skipping 111 matching lines @@
   } else {
     print('good');
   }
 }""","""
 function() {
   V.foo();
   P.print("good");
   return null;
 }"""),
 ];
+
+void main() {
+  runTests(tests);
+}