Check return value when validating in benchmark program
Shuffle branch targets in memzero/memset for better performance
Optimize small size unaligned case for NEON, and enforce Thumb2 dependency

Optimize the small size unaligned case with NEON instructions which
automatically handle alignment.

Fix broken memcpy compilation when NEON is enabled, but Thumb2 disabled by
only compiling memcpy for NEON if Thumb2 is enabled.