Flaky test org.eclipse.jetty.ee9.servlet.ContextScopeListenerTest

[olamy]

With 12.1.x

Expected: <[enterScope /initialPath, doGet, enterScope /initialPath, asyncRunnable, exitScope /initialPath, asyncDispatch, exitScope /dispatch]>
     but: was <[enterScope /initialPath, doGet, enterScope /initialPath, asyncRunnable, asyncDispatch, exitScope /initialPath, exitScope /dispatch]>
	at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)
	at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:6)
	at [email protected]/org.eclipse.jetty.ee9.servlet.ContextScopeListenerTest.assertHistory(ContextScopeListenerTest.java:143)
	at [email protected]/org.eclipse.jetty.ee9.servlet.ContextScopeListenerTest.testAsyncServlet(ContextScopeListenerTest.java:130)
	at java.base/java.lang.reflect.Method.invoke(Method.java:569)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)
```