Fixed workflowsWithFailedPromisesCanBeCancelled test (#199)

Author: mfateev

src/test/java/com/uber/cadence/workflow/WorkflowTest.java

@@ -661,10 +661,8 @@ public String execute(String taskList) {
   }
 
   @Test
-  public void WorkflowsWithFailedPromisesCanBeCancelled() {
-    worker.registerWorkflowImplementationTypes(
-        TestCancellationForWorkflowsWithFailedPromises.class);
-    testEnvironment.start();
+  public void workflowsWithFailedPromisesCanBeCancelled() {
+    startWorkerFor(TestCancellationForWorkflowsWithFailedPromises.class);
     WorkflowStub client =
         workflowClient.newUntypedWorkflowStub(
             "TestWorkflow1::execute", newWorkflowOptionsBuilder(taskList).build());