8146395: Add inline qualifier in oop.hpp and fix inlining in gc files
Summary: Fix remaining issues after 8146401. Also fix windows VS2010 linkage problem (g1OopClosures.hpp).
Reviewed-by: stefank, mgerdin

8139341: Hide ExtendedOopClosure::_ref_processor
Summary: Make ExtendedOopClosure::_ref_processor private.
Reviewed-by: mgerdin, sjohanss

8080877: Don't use workers()->total_workers() when walking G1CollectedHeap::_task_queues
Reviewed-by: jmasa, drwhite

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