8181917: Refactor UL LogStreams to avoid using resource area
Reviewed-by: ehelin, mlarsson

8159073: : Error handling incomplete when creating GC threads lazily
Reviewed-by: drwhite, tschatzl, sangheki

8157240: GC task trace logging is incomprehensible
Reviewed-by: tschatzl, redestad

6858051: Create GC worker threads dynamically
Reviewed-by: tschatzl, drwhite

8152632: Rename LogHandle(...) to Log(...)
Reviewed-by: brutisso, mlarsson, rprotacio

8153186: Convert TraceGCTaskThread to use unified logging
Reviewed-by: mgerdin, tschatzl

8145092: Use Unified Logging for the GC logging
Summary: JEP-271. VM changes contributed by brutisso, test changes contributed by david.
Reviewed-by: sjohanss, david, brutisso
Contributed-by: bengt.rutisson@oracle.com, david.lindholm@oralce.com

8138707: TestPromotionEventWithParallelScavenge.java crashes using undefined GC id.
Reviewed-by: mgerdin, jwilhelm

8138863: Refactor WaitForBarrierGCTask
Reviewed-by: mgerdin, jwilhelm

8138862: Remove some unused code and subclasses in gcTaskManager.hpp/cpp
Reviewed-by: mgerdin, jwilhelm

8080775: Better argument formatting for assert() and friends
Reviewed-by: kbarrett, pliden

8081382: Make flags ParallelGCThreads and ConcGCThreads of type uint
Reviewed-by: drwhite, stefank

8079792: GC directory structure cleanup
Reviewed-by: brutisso, stefank, david