Fix a couple of bugs in VM cctest running.

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 2c9f591b06c773061df0256da3713fb4fb8f017f..f6d1ab21f9dd029fc5db52cc9b352614c24ba9b6 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -30,6 +30,10 @@ class CCTestListerIsolate extends Isolate {
           line = stdoutStream.readLine();
         }
       };
+      p.errorHandler = (error) {
+        print("Failed to list tests: $runnerPath --list");
+        replyTo.send("");
+      };
       p.exitHandler = (code) {
         if (code < 0) {
           print("Failed to list tests: $runnerPath --list");
@@ -40,6 +44,7 @@ class CCTestListerIsolate extends Isolate {
         }
         replyTo.send("");
       };
+      port.close();
     });
   }
 }
@@ -94,8 +99,6 @@ class CCTestSuite implements TestSuite {
                           configuration,
                           completeHandler,
                           expectations));
-
-      receiveTestName.receive(testNameHandler);
     }
   }