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

frog/tests/await/mint_maker_rpc_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
+
 // Copy of MintMakerRpcTest (under tests/isolate/src/) but rewritten using
 // await.
 
 #import('../../../await/samples/mintmaker/mintmaker.dart');
 
 main() {
   print("starting test");
   MintProxy mint = new MintIsolate().open();
 
   PurseProxy purse1 = await mint.createPurse(100);
@@ skipping 31 matching lines @@
 
   // Check that the balance in each purse is unchanged from
   // before we attempted to do the overdraft.
   Expect.equals(balance1, await purse1.queryBalance());
   Expect.equals(balance2, await purse2.queryBalance());
 
   // OK, we're all done now, close down the mint isolate
   print(await mint.close());
   print("exit main");
 }