Summary: Use SSE4.2 and AVX2 instructions for encodeArray intrinsic.
Reviewed-by: roland

Summary: use 256bit vpxor,vptest instructions in String.compareTo() and equals() intrinsics.
Reviewed-by: twisti

Summary: use 'rep stosb' instead of 'rep stosq' when fast-string operations are available.
Reviewed-by: twisti, roland

Reviewed-by: kvn, twisti
Contributed-by: NBharadwaj Yadavalli <bharadwaj.yadavalli@oracle.com>

Reviewed-by: kvn