[lworld] References to biased pattern remain in markWord::is_unlocked()

markWord::is_unlocked() still uses biased pattern, causes fallback to klass layout

* add more gtest mark word tests
* assert any use of "biased locking" (there are some existing "has_biased_pattern()" asserts not guarded "UseBiasedLocking")
* remove biased_lock_mask_in_place from is_unlocked