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

src/arm/macro-assembler-arm.h

 // Copyright 2012 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_ARM_MACRO_ASSEMBLER_ARM_H_
 #define V8_ARM_MACRO_ASSEMBLER_ARM_H_
 
 #include "src/assembler.h"
 #include "src/frames.h"
 #include "src/globals.h"
@@ skipping 760 matching lines @@
                                  Label* gc_required);
 
   // 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 also
   // when control continues at the gc_required label.
   void AllocateHeapNumber(Register result,
                           Register scratch1,
                           Register scratch2,
                           Register heap_number_map,
                           Label* gc_required,
-                          TaggingMode tagging_mode = TAG_RESULT,
-                          MutableMode mode = IMMUTABLE);
+                          TaggingMode tagging_mode = TAG_RESULT);
   void AllocateHeapNumberWithValue(Register result,
                                    DwVfpRegister value,
                                    Register scratch1,
                                    Register scratch2,
                                    Register heap_number_map,
                                    Label* gc_required);
 
   // Copies a fixed number of fields of heap objects from src to dst.
   void CopyFields(Register dst,
                   Register src,
@@ skipping 822 matching lines @@
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_MACRO_ASSEMBLER_ARM_H_