lingering step 2 of the test rename overhaul: make await tests also a directory

frog/tests/await/while_loop_test.dart

 // Copyright (c) 2011, 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.
 
+// The next line is used to tell test.dart that this test is run by invoking
+// awaitc.dart and passing this file as an argument (e.g. frog
+// frog/await/awaitc.dart test.dart):
+// VMOptions=frog/await/awaitc.dart
+
 // Await within a loop:
 
 #import("await_test_helper.dart");
 
 main() {
   var x = 0;
   while (x < 3) {
     final f = futureOf(1);
     final t = await f;
     x += t;
@@ skipping 16 matching lines @@
 //         x += t;
 //         _loop_1();
 //       });
 //       Futures.propagateError(f, _ret);
 //       return;
 //     }
 //     _after_loop_1();
 //   }();
 //   return _ret;
 // }