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
StoreFpuToOffset.

Change-Id: I0228a4a2ce6c801eeb5b46952b8330e14468deb3
diff --git a/compiler/optimizing/code_generator_mips64.h b/compiler/optimizing/code_generator_mips64.h
index 08e5615..c836f83 100644
--- a/compiler/optimizing/code_generator_mips64.h
+++ b/compiler/optimizing/code_generator_mips64.h
@@ -27,10 +27,6 @@
 namespace art {
 namespace mips64 {
 
-// Use a local definition to prevent copying mistakes.
-static constexpr size_t kMips64WordSize = kMips64PointerSize;
-
-
 // InvokeDexCallingConvention registers
 
 static constexpr GpuRegister kParameterCoreRegisters[] =
@@ -274,9 +270,9 @@
 
   void Move(HInstruction* instruction, Location location, HInstruction* move_for) OVERRIDE;
 
-  size_t GetWordSize() const OVERRIDE { return kMips64WordSize; }
+  size_t GetWordSize() const OVERRIDE { return kMips64DoublewordSize; }
 
-  size_t GetFloatingPointSpillSlotSize() const OVERRIDE { return kMips64WordSize; }
+  size_t GetFloatingPointSpillSlotSize() const OVERRIDE { return kMips64DoublewordSize; }
 
   uintptr_t GetAddressOf(HBasicBlock* block) const OVERRIDE {
     return assembler_.GetLabelLocation(GetLabelOf(block));