[Interpreter] Add ForInPrepare runtime function which returns a ObjectTriple.

src/arm64/macro-assembler-arm64.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ARM64_MACRO_ASSEMBLER_ARM64_H_
 #define V8_ARM64_MACRO_ASSEMBLER_ARM64_H_
 
 #include <vector>
 
 #include "src/arm64/assembler-arm64.h"
@@ skipping 19 matching lines @@
 #endif
 
 
 namespace v8 {
 namespace internal {
 
 // Give alias names to registers for calling conventions.
 // TODO(titzer): arm64 is a pain for aliasing; get rid of these macros
 #define kReturnRegister0 x0
 #define kReturnRegister1 x1
+#define kReturnRegister2 x2
 #define kJSFunctionRegister x1
 #define kContextRegister cp
 #define kInterpreterAccumulatorRegister x0
 #define kInterpreterRegisterFileRegister x18
 #define kInterpreterBytecodeOffsetRegister x19
 #define kInterpreterBytecodeArrayRegister x20
 #define kInterpreterDispatchTableRegister x21
 #define kJavaScriptCallArgCountRegister x0
 #define kJavaScriptCallNewTargetRegister x3
 #define kRuntimeCallFunctionRegister x1
@@ skipping 2202 matching lines @@
 #error "Unsupported option"
 #define CODE_COVERAGE_STRINGIFY(x) #x
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 #endif  // V8_ARM64_MACRO_ASSEMBLER_ARM64_H_