Revert "With this change 'tools/test.py -cdartk vm' will run vm tests with Dart Frontend parser."

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
diff --git a/tools/testing/dart/test_suite.dart b/tools/testing/dart/test_suite.dart
index 08362f36542656717f986f372c4cf43de31e5247..cc741897fe91378f46760f33885c3947e0848713 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -473,12 +473,6 @@ class CCTestSuite extends TestSuite {
     var expectations = testExpectations.expectations('$testPrefix$testName');
 
     var args = TestUtils.standardOptions(configuration);
-    var compilerConfiguration = new CompilerConfiguration(configuration);
-    if (compilerConfiguration.useDFE) {
-      args.add('--use-dart-frontend');
-      // '--dfe' has to be the first argument for run_vm_test to pick it up.
-      args.insert(0, '--dfe=$buildDir/gen/kernel-service.dart.snapshot');
-    }
     args.add(testName);
 
     var command = CommandBuilder.instance.getProcessCommand(