VM: [Kernel] Switch to DFE for testing -c dartk configuration.

tools/testing/dart/runtime_configuration.dart

Index: tools/testing/dart/runtime_configuration.dart
diff --git a/tools/testing/dart/runtime_configuration.dart b/tools/testing/dart/runtime_configuration.dart
index c077e7d9690c7f44aaf9b68717971f9a03ceaa07..d0b90f031a47e409f34b527ceaca7a55df16b1c1 100644
--- a/tools/testing/dart/runtime_configuration.dart
+++ b/tools/testing/dart/runtime_configuration.dart
@@ -227,6 +227,8 @@ class StandaloneDartRuntimeConfiguration extends DartVmRuntimeConfiguration {
       CommandArtifact artifact,
       List<String> arguments,
       Map<String, String> environmentOverrides) {
+    final bool needsDFERunner = suite.configuration['compiler'] == 'dartk' &&
+        !suite.configuration['use-standalone-dartk'];
     String script = artifact.filename;
     String type = artifact.mimeType;
     if (script != null &&
@@ -236,7 +238,7 @@ class StandaloneDartRuntimeConfiguration extends DartVmRuntimeConfiguration {
     }
     String executable = suite.dartVmBinaryFileName;
     return <Command>[
-      commandBuilder.getVmCommand(executable, arguments, environmentOverrides)
+      commandBuilder.getVmCommand(executable, arguments, environmentOverrides, needsDFERunner: needsDFERunner)
     ];
   }
 }