Create a standalone test directory and move tests in runtime/tests/dart (mostly) to that directory.

dart/tests/corelib/src/GrowableObjectArrayVMTest.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.
 
 #library("GrowableObjectArrayTest.dart");
 #import("dart:coreimpl");
 
 class GrowableObjectArrayTest {
 
   static void testOutOfBoundForIndexOf() {
@@ skipping 72 matching lines @@
     GrowableObjectArray<int> h = new GrowableObjectArray<int>.withCapacity(10);
     Array constArray = const [0, 1, 2, 3, 4];
     h.addAll(constArray);
     Expect.equals(5, h.length);
   }
 }
 
 main() {
   GrowableObjectArrayTest.testMain();
 }