[PATCH] [AArch64] Improve and enable the SeparateConstOffsetFromGEP for AArch64 backend.

[Jingyue Wu]

Did you try pinning the benchmark on one CPU? Scheduling can significantly
disturb the benchmark results. Also, if your CPU has any boosting feature
(similar to Intel's turbo boost), try disabling that. One of our folks,
Mark, found that can make benchmarking sensitive too.

Jingyue

http://reviews.llvm.org/D5864