Add dummpy impl to get old error-prone work

Author: vancexu

src/main/java/com/uber/cadence/internal/testservice/TestWorkflowMutableStateImpl.java

@@ -347,6 +347,9 @@ private void processDecision(
         processRequestCancelExternalWorkflowExecution(
             ctx, d.getRequestCancelExternalWorkflowExecutionDecisionAttributes());
         break;
+      case UpsertWorkflowSearchAttributes:
+        // TODO: https://github.com/uber/cadence-java-client/issues/360
+        break;
     }
   }