RFR(xxs): 8212913: (Nested)ThreadsListHandleInErrorHandlingTest need to disable ShowRegistersOnAssert

[Thomas Stüfe]

Hi all,

may I please have reviews for this smallish patch.

Bug: https://bugs.openjdk.java.net/browse/JDK-8212913
cr: http://cr.openjdk.java.net/~stuefe/webrevs/8212913-fix-ThreadsListHandleInErrorHandlingTest-with-ShowRegistersOnAssert/webrev.00/webrev/

This patch fixes NestedThreadsListHandleInErrorHandlingTest and
ThreadsListHandleInErrorHandlingTest when run with
-XX:+ShowRegistersOnAssert. Please see bug description for further
details.

Thanks, Thomas