Fix test case error

Author: ningyougang

tests/src/test/scala/org/apache/openwhisk/core/containerpool/test/ContainerPoolTests.scala

@@ -329,9 +329,8 @@ class ContainerPoolTests
     val feed = TestProbe()
 
     val pool =
-      system.actorOf(
-        ContainerPool
-          .props(factory, poolConfig(MemoryLimit.STD_MEMORY), feed.ref, List(PrewarmingConfig(1, exec, memoryLimit))))
+      system.actorOf(ContainerPool
+        .props(factory, poolConfig(MemoryLimit.STD_MEMORY * 2), feed.ref, List(PrewarmingConfig(1, exec, memoryLimit))))
     containers(0).expectMsg(Start(exec, memoryLimit))
     containers(0).send(pool, NeedWork(preWarmedData(exec.kind)))
     pool ! runMessage