RFR [11]: 2018-10-23, Bulk backports to sh/jdk11

[Aleksey Shipilev]

http://cr.openjdk.java.net/~shade/shenandoah/backports/jdk11-20181023/webrev.01/

Let's get our every-Monday (ahem) backports back in order:

 [backport] Filter upstream tests for Shenandoah (part 1: tier1_gc)
 [backport] Avoid false sharing by padding the ShenandoahEvacOOMHandler field in ShenandoahHeap
 [backport] Support VerifyBeforeGC and VerifyAfterGC VM options
 [backport] fix for PhaseIdealLoop::clone_loop_predicates_fix_mem()
 [backport] Skip pre-evac verification and pacing on shortcut cycle path
 [backport] Filter out TestPromotionToSurvivor.java test for Shenandoah
 [backport] Protect more internal code from false sharing

Testing: tier3_gc_shenandoah {fastdebug|release}

-Aleksey