`HttpClientContinueTest.testNoExpect100ContinueThen100ContinueThenRedirectThen100ContinueThenResponse()` is flaky

[lorban]

Jetty version(s) 12.0.x

Jetty Environment ee10

Description org.eclipse.jetty.ee10.test.client.transport.HttpClientContinueTest.testNoExpect100ContinueThen100ContinueThenRedirectThen100ContinueThenResponse() sometimes fails with:

org.opentest4j.AssertionFailedError: expected: <true> but was: <false>
	at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
	at org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
	at org.junit.jupiter.api.AssertTrue.failNotTrue(AssertTrue.java:63)
	at org.junit.jupiter.api.AssertTrue.assertTrue(AssertTrue.java:36)
	at org.junit.jupiter.api.AssertTrue.assertTrue(AssertTrue.java:31)
	at org.junit.jupiter.api.Assertions.assertTrue(Assertions.java:183)
	at org.eclipse.jetty.ee10.test.client.transport.HttpClientContinueTest.testNoExpect100ContinueThen100ContinueThenRedirectThen100ContinueThenResponse(HttpClientContinueTest.java:950)

See: https://github.com/jetty/jetty.project/pull/11721/checks?check_run_id=24544567094