Intermittent failures in DynamicJNDIContextEJBInvocationTestCase

We're starting to see quite frequent intermittent failures of DynamicJNDIContextEJBInvocationTestCase.

Looking at the history[1] it seems that this first started popping up with the EJB Client Interceptors PR.[2]

[1] https://ci.wildfly.org/project.html?projectId=WF_PullRequest&buildTypeId=&tab=testDetails&testNameId=3633635619745467113&order=TEST_STATUS_DESC&branch_WF_PullRequest=__all_branches__&itemsCount=50

[2] https://github.com/wildfly/wildfly/pull/12490

I'm putting Blocker priority on this because it's a potential regression. But if it's not a regression, just a test that needs improvement, please lower the Priority right away, i.e. don't wait to fix the test.