Revert "Replace HeapNumber as doublebox with an explicit MutableHeapNumber."

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/globals.h"
@@ skipping 1353 matching lines @@
   // Allocates a heap number or jumps to the gc_required label if the young
   // space is full and a scavenge is needed.
   // All registers are clobbered.
   // If no heap_number_map register is provided, the function will take care of
   // loading it.
   void AllocateHeapNumber(Register result,
                           Label* gc_required,
                           Register scratch1,
                           Register scratch2,
                           CPURegister value = NoFPReg,
-                          CPURegister heap_number_map = NoReg,
-                          MutableMode mode = IMMUTABLE);
+                          CPURegister heap_number_map = NoReg);
 
   // ---------------------------------------------------------------------------
   // Support functions.
 
   // Try to get function prototype of a function and puts the value in the
   // result register. Checks that the function really is a function and jumps
   // to the miss label if the fast checks fail. The function register will be
   // untouched; the other registers may be clobbered.
   enum BoundFunctionAction {
     kMissOnBoundFunction,
@@ skipping 933 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_