The test test_handle_interrupted? may fail at test/mri/ruby/test_thread.rb:862 due to flaws in Thread#handle_interrupt logic. If the handling is allowing exceptions to be thrown that should be masked, it could trigger push of :ng1 earlier in the test, causing a sporadic failure as seen in this job: https://travis-ci.org/jruby/jruby/jobs/430135641

I am quarantining this test until we can determine if it is a flawed test or a bug in handle_interrupt.

FWIW I have stepped through handle_interrupt and been unable to reproduce the issue locally, so it may involve more complicated timing than can be simulated in a debug session.