Reviewed-by: apetrusenko, ysr

Summary: Renamed Reference{Policy,Pocessor} methods from snap{,_policy}() to setup{,_policy}()
Reviewed-by: apetrusenko

Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa

Summary: Avoid growth of a GrowableArray backend of HeapRegionSeq.
Reviewed-by: tonyp, jcoomes

Summary: Introduce parallel heap verification in G1.
Reviewed-by: jcoomes, apetrusenko

Summary: Under certain circumstances, two cleanup threads can claim and process the same region.
Reviewed-by: apetrusenko, ysr

6652160: G1: assert(cur_used_bytes == _g1->recalculate_used(),"It should!") at g1CollectorPolicy.cpp:1425
Summary: In attempt_allocation_slow() wait for the concurrent cleanup to complete before modifying _summary_bytes_used.
Reviewed-by: jmasa, apetrusenko

6723570: G1: assertion failure: p == current_top or oop(p)->is_oop(),"p is not a block start" (revisited!)
Summary: Fixed the incorrect assigment to G1OffsetTableContigSpace::_gc_time_stamp. Also added a little more paranoia to operations on a global timestamp.
Reviewed-by: tonyp

6702387: G1: assertion failure: assert(p == current_top || oop(p)->is_oop(),"p is not a block start")
Summary: Do not coalesce dead and moved objects when removing self-forwarding pointers during the evacuation failure. Also fixed a issue in a BOT refinement code for TLABs.
Reviewed-by: tonyp, jcoomes

Summary: First mercurial integration of the code for the Garbage-First garbage collector.
Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr