added this check to prevent a suspended JavaThread to transition back to java without noticing it was suspended. Since
, a JavaThread executing HandshakeState::process_by_self() will never become safe. It comes from an unsafe state and remains unsafe, so it cannot be suspended during that time. Removing this check also removes one of the reasons SafepointMechanism::process_if_requested() is recursive (the other one remains SafepointSynchronize::block()).