Refine previous modifications in CompletableFutureTaskTest

dubbo-common/src/test/java/org/apache/dubbo/common/concurrent/CompletableFutureTaskTest.java

@@ -87,6 +87,5 @@ public void testCustomExecutor() {
             return 0;
         });
         completableFuture.thenRunAsync(mock(Runnable.class), verify(mockedExecutor));
-        verify(mockedExecutor).execute(any(Runnable.class));
     }
 }