A Web Socket test intermittently fails in apex-pdp.

In the Web Socket unit test, sometimes the server does not start quickly enough and is not available when the wek socket client connects. This review changes the unit test to wait for up to 2 seconds for the web socket server to come up.

01:12:14 2020-05-15 00:12:14,387 Apex [main] WARN o.o.p.a.c.i.m.s.WsStringMessageClient - web socket event consumer client to "ws://localhost:44441" start failed
01:12:14 java.lang.IllegalStateException: Could not connect to the server
01:12:14 at org.onap.policy.apex.core.infrastructure.messaging.impl.ws.client.MessagingClient.startConnection(MessagingClient.java:89)
01:12:14 at org.onap.policy.apex.core.infrastructure.messaging.stringmessaging.WsStringMessageClient.start(WsStringMessageClient.java:83)
01:12:14 at org.onap.policy.apex.core.infrastructure.messaging.EndToEndStringMessagingTest.testEndToEndMessaging(EndToEndStringMessagingTest.java:61)
01:12:14 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
01:12:14 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
01:12:14 at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
01:12:14 at java.base/java.lang.reflect.Method.invoke(Method.java:566)
01:12:14 at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
01:12:14 at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
01:12:14 at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
01:12:14 at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
01:12:14 at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
01:12:14 at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
01:12:14 at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
01:12:14 at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
01:12:14 at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
01:12:14 at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
01:12:14 at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
01:12:14 at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
01:12:14 at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
01:12:14 at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
01:12:14 at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
01:12:14 at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
01:12:14 at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:365)
01:12:14 at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:273)
01:12:14 at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:238)
01:12:14 at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:159)
01:12:14 at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:377)
01:12:14 at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:138)
01:12:14 at org.apache.maven.surefire.booter.ForkedBooter.run(ForkedBooter.java:465)
01:12:14 at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:451)