RFR [11]: 2018-10-18, Bulk backports to sh/jdk11

[Aleksey Shipilev]

http://cr.openjdk.java.net/~shade/shenandoah/backports/jdk11-20181018/webrev.01/

There were many unclean applies and specific whitespace changes, please take a careful look.

Changes include:

 [backport] Fix and enable suspendible workers by default
 [backport] Fix up superfluous changes against upstream
 [backport] Move SATB flushing machinery out of shared code
 [backport] Readjust ShenandoahStrDedupStress test to avoid timeout
 [backport] Remove idle-on-uncommit support
 [backport] Assert that Shenandoah does not trip JDK-8211926
 [backport] Added a few missed worker sessions for worker tasks
 [backport] Remove unused SA ShenandoahHeapRegionSet.java
 [backport] lucene fixes
 [backport] Add JFR parallel and concurrent events (infrastructure)
 [backport] Remove ShenandoahCompileCheck
 [backport] Clean up Shenandoah configurations in shared tests
 [backport] Remove leftover from oopsHierarchy.hpp
 [backport] A few more missing object equals barriers
 [backport] c2 verification pass fixes for CAS
 [backport] Move HdrSeq and BinaryMagnitudeSeq into Shenandoah utilities
 [backport] Integrate Shenandoah tests to upstream test groups
 [backport] Enable NUMA by default
 [backport] Force termination logic is inverted
 [backport] Reinstate single-threaded reference processing
 [backport] Don't attempt to leave STS in final-traversal, where we never enter STS
 [backport] Need to step over GC barriers in Node::eqv_uncast()
 [backport] Consistenly order STS scope outside of OOM scope to avoid deadlocks
 [backport] Disable suspendible workers (again)
 [backport] Fixed ShenandoahStrDedupStress test that causes negative index OOB exception

Testing: tier3_gc_shenandoah {fastdebug|release}

Thanks,
-Aleksey