[11] 2020-05-07, Bulk backports to sh/jdk11

[Aleksey Shipilev]

https://cr.openjdk.java.net/~shade/shenandoah/backports/jdk11-20200507/webrev.01/

Here is a bunch of simpler backports for 11u:

 [backport] 8224573: Fix windows build after JDK-8221507
 [backport] 8243238: Shenandoah: explicit GC request should wait for a complete GC cycle
 [backport] 8243307: Shenandoah: remove ShCollectionSet::live_data
 [backport] 8243301: Shenandoah: ditch ShenandoahAllowMixedAllocs
 [backport] 8243291: Shenandoah: no need to retire TLABs at Init Update Refs
 [backport] 8243395: Shenandoah: demote guarantee in ShenandoahPhaseTimings::record_workers_end
 [backport] 8243460: Shenandoah: purge init_update_refs_prepare counter
 [backport] 8243463: Shenandoah: ditch total_pause counters
 [backport] 8243464: Shenandoah: print statistic counters in time order
 [backport] 8243465: Shenandoah: ditch unused pause_other, conc_other counters

Testing: hotspot_gc_shenandoah {fastdebug,release}

-- 
Thanks,
-Aleksey