The fix for JDK-8132849 causes timeouts in 11.0.8-oracle that disappear with-XX:-ThreadLocalHandshakes. Most likely some dependent fixes are missing. I'm backing JDK-8132849 and follow-up fix JDK-8211129 out for now.
JDK-8243397Increased stop time in cleanup phase because of single-threaded walk of thread stacks in NMethodSweeper::mark_active_nmethods()
JDK-8243398compiler/whitebox/ForceNMethodSweepTest.java fails after JDK-8132849