TempFileProviderService threads consume high CPU

TempFileProviderService threads consume high CPU as they poll their non empty task queue. This is ultimately due to a flaw in the JDK ThreadPoolExecutor code (https://bugs.openjdk.java.net/browse/JDK-8129861), impacting ScheduledThreadPoolExecutors that use a core size of 0 and a default 0 keepalive timeout.

While the executor queue is not empty, the executor does not allow the pool to go below 1 thread. So the one remaining work thread keeps looping over its poll call with a 0 timeout. Options to protect JBoss from this are:

1) Set a keepalive timeout on the executor so the poll has a duration and the worker run loop isn't so busy
2) Or set the Executor core pool size to >0. The worker thread would then use a blocking take() call on its queue instead of a constant 0 second poll calls. The side effect of this change is that the thread pool wouldn't ever drop back down to 0.