Reuse -cdartk for vm testing with Dart Frontend parser.

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 2022 matching lines @@
     }
     if (compiler == "dart2js" && configuration["cps_ir"]) {
       args.add("--use-cps-ir");
     }
     if (compiler == "dart2js" && configuration["fast_startup"]) {
       args.add("--fast-startup");
     }
     if (compiler == "dart2js" && configuration["dart2js_with_kernel"]) {
       args.add("--use-kernel");
     }
+    if (compiler == "none" &&
+        configuration["kernel_snapshot_to_use_in_vm"] != '') {
+      // Kernel snapshot argument should be first in the list.
+      args.insert(0,
+          "--run_vm_test_with_kernel_snapshot=${configuration['kernel_snapshot_to_use_in_vm']}");
+      args.add("--use_dart_frontend");

[siva, 2017/05/15 04:42:56]

Why not use the same scheme as used with the compiler=dartk option in the
regular testing it picks up the kernel snapshot from
{buildDir}/gen/kernel-service.dart.snapshot

[aam, 2017/05/16 00:18:02]

If we are to support vm testing with or without kernel parser we still would
have to introduce an option. Or were you thinking something along the lines of
introducing new compiler(something like none_dfe as alternative to none)?
If we are to introduce an option, I thought we might as well make it a
string(snapshot name), rather than a boolean option(dfe)?

[siva, 2017/05/17 18:36:46]

I was thinking if we changed test_configuration.dart to include compiler ==
dartk we would be able to reuse all the stuff that is setup for dartk in the
regular tests

            (conf['compiler'] == 'none' || conf['compiler'] == 'dartk') &&
            conf['runtime'] == 'vm' &&
            key == 'vm') {
          // vm tests contain both cc tests (added here) and dart tests (added
          // in [TEST_SUITE_DIRECTORIES]).
          testSuites.add(new VMTestSuite(conf));

Then we should be able to run the test as 

tools/test.py -cdartk vm

+    }
     return args;
   }
 
   static bool isBrowserRuntime(String runtime) {
     const BROWSERS = const [
       'drt',
       'dartium',
       'ie9',
       'ie10',
       'ie11',
@@ skipping 176 matching lines @@
       }
       if (path.length > WINDOWS_SHORTEN_PATH_LIMIT) {
         ++shortNameCounter;
         var pathEnd = path.substring(path.length - WINDOWS_PATH_END_LENGTH);
         path = "short${shortNameCounter}_$pathEnd";
       }
     }
     return path;
   }
 }