Add G1BiasedArray<T> that is an array where each element represents a fixed-sized subdivision of the heap. Use this abstraction to refactor the HeapRegionSeq class.
Reviewed-by: brutisso
Change the type of fields / variables / etc. that represent region counts and indeces from size_t to uint.
Reviewed-by: iveresov, brutisso, jmasa, jwilhelm
Extend the SA to recognize the G1CollectedHeap and implement any code that's needed by our serviceability tools (jmap, jinfo, jstack, etc.) that depend on the SA.
Reviewed-by: never, poonam, johnc
