make test TEST=gc/arguments/TestShrinkHeapInSteps.java JTREG="VM_OPTIONS=-XX:+UseConcMarkSweepGC"

Gets assert:

Crash: Internal Error ...mutex.cpp...assert(thread->is_Java_thread() || !do_safepoint_check || _safepoint_check_required != Monitor::_safepoint_check_never) failed: NonJavaThread should not check for safepoint

David didn't like the assert so I'll remove it. There are some CMS locks that are safepoint_check_never but are acquired without _no_safepoint_check_flag and I haven't been able to non-intermittently find them all.