RFR (sh/8): Revert obsolete shared-code changes in runtime synchronizer code

[Roman Kennke]

This reverts shared-code changes in synchronizer.cpp and
biasedLocking.cpp in shenandoah/jdk8. Those are no longer needed because
of LRB. Functionally it should be equivalent, but better to keep the
upstream versions and trim down the Shenandoah diff.

Webrev:
http://cr.openjdk.java.net/~rkennke/shjdk8-remove-cruft2/webrev.00/

Testing: hotspot_gc_shenandoah

Can I please get a review?

Thanks,
Roman