MIPS64: Remove unaligned memory access from art generated code

Unaligned memory access was caused by sd, ld, ldc1 and sdc1
instructions. Check if offset is unaligned and replace it
with two 32 bit memory accesses, if so.

Added assembler tests for new instructions, as well as assembler
tests for LoadFromOffset, LoadFpuFromOffset, StoreToOffset and

Change-Id: I0228a4a2ce6c801eeb5b46952b8330e14468deb3
8 files changed