LocalConnectorTest.testExpect100ContinueContentAvailable() is flaky

[lorban]

Jetty version(s)
12.0.x

Description
org.eclipse.jetty.server.LocalConnectorTest.testExpect100ContinueContentAvailable() sometimes fails with:

java.lang.ArrayIndexOutOfBoundsException: arraycopy: last destination index 289 out of bounds for byte[130]
	at java.base/java.lang.System.arraycopy(Native Method)
	at java.base/java.lang.String.getBytes(String.java:4722)
	at java.base/java.lang.AbstractStringBuilder.putStringAt(AbstractStringBuilder.java:1751)
	at java.base/java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:588)
	at java.base/java.lang.StringBuilder.append(StringBuilder.java:179)
	at [email protected]/org.eclipse.jetty.server.LoggerDebugTest$CaptureDebugLogging.out(LoggerDebugTest.java:135)
	at [email protected]/org.eclipse.jetty.server.LoggerDebugTest$CaptureDebugLogging.println(LoggerDebugTest.java:150)
	at [email protected]/org.eclipse.jetty.logging.StdErrAppender.emit(StdErrAppender.java:100)
	at [email protected]/org.eclipse.jetty.logging.JettyLogger.emit(JettyLogger.java:613)
	at [email protected]/org.eclipse.jetty.logging.JettyLogger.info(JettyLogger.java:338)
	at [email protected]/org.eclipse.jetty.server.Server.doStop(Server.java:631)
	at [email protected]/org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:132)
	at [email protected]/org.eclipse.jetty.server.LocalConnectorTest.dispose(LocalConnectorTest.java:52)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at java.base/java.util.concurrent.RecursiveAction.exec(RecursiveAction.java:194)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:387)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1312)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1843)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1808)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:188)

See: https://jenkins.webtide.net/blue/organizations/jenkins/jetty.project/detail/PR-11777/4/tests