8043029: Change 8037816 breaks HS build with older GCC versions which don't support diagnostic pragmas
8043164: Format warning in traceStream.hpp
Summary: Backport of main fix + two corrections, enables clang compilation, turns on format attributes, corrects/mutes warnings
Reviewed-by: kvn, coleenp, iveresov, twisti

Summary: Pad and cache-align BiasedMappedArray instances by default to avoid performance variability problems due to false sharing, as instances of this data structures are typically used for performance sensitive code.
Reviewed-by: brutisso, stefank

Summary: Using pointer_delta to avoid overflowing pointer calculation.
Reviewed-by: jwilhelm, ehelin

Summary: 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