ARM64: Make the VIXL macro assembler part of ART ARM64's assembler.

This avoids a dynamic allocation of the VIXL macro assembler.

Change-Id: I4cd62678d0978f1ad6f32ea0ce7279e09152be38
diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc
index 06d1148..e3a9d27 100644
--- a/compiler/optimizing/intrinsics_arm64.cc
+++ b/compiler/optimizing/intrinsics_arm64.cc
@@ -26,7 +26,6 @@
 #include "mirror/string.h"
 #include "thread.h"
 #include "utils/arm64/assembler_arm64.h"
-#include "utils/arm64/constants_arm64.h"
 
 using namespace vixl::aarch64;  // NOLINT(build/namespaces)
 
@@ -62,14 +61,14 @@
 }  // namespace
 
 MacroAssembler* IntrinsicCodeGeneratorARM64::GetVIXLAssembler() {
-  return codegen_->GetAssembler()->vixl_masm_;
+  return codegen_->GetVIXLAssembler();
 }
 
 ArenaAllocator* IntrinsicCodeGeneratorARM64::GetAllocator() {
   return codegen_->GetGraph()->GetArena();
 }
 
-#define __ codegen->GetAssembler()->vixl_masm_->
+#define __ codegen->GetVIXLAssembler()->
 
 static void MoveFromReturnRegister(Location trg,
                                    Primitive::Type type,
@@ -782,7 +781,7 @@
   DCHECK((type == Primitive::kPrimInt) ||
          (type == Primitive::kPrimLong) ||
          (type == Primitive::kPrimNot));
-  MacroAssembler* masm = codegen->GetAssembler()->vixl_masm_;
+  MacroAssembler* masm = codegen->GetVIXLAssembler();
   Location base_loc = locations->InAt(1);
   Register base = WRegisterFrom(base_loc);      // Object pointer.
   Location offset_loc = locations->InAt(2);
@@ -916,7 +915,7 @@
                          bool is_volatile,
                          bool is_ordered,
                          CodeGeneratorARM64* codegen) {
-  MacroAssembler* masm = codegen->GetAssembler()->vixl_masm_;
+  MacroAssembler* masm = codegen->GetVIXLAssembler();
 
   Register base = WRegisterFrom(locations->InAt(1));    // Object pointer.
   Register offset = XRegisterFrom(locations->InAt(2));  // Long offset.
@@ -1035,7 +1034,7 @@
 }
 
 static void GenCas(LocationSummary* locations, Primitive::Type type, CodeGeneratorARM64* codegen) {
-  MacroAssembler* masm = codegen->GetAssembler()->vixl_masm_;
+  MacroAssembler* masm = codegen->GetVIXLAssembler();
 
   Register out = WRegisterFrom(locations->Out());                  // Boolean result.