X87: [Atomics] Make Atomics.store a builtin using TF.

src/x87/assembler-x87.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 630 matching lines @@
   void cld();
 
   // Repetitive string instructions.
   void rep_movs();
   void rep_stos();
   void stos();
 
   // Exchange
   void xchg(Register dst, Register src);
   void xchg(Register dst, const Operand& src);
+  void xchg_b(Register reg, const Operand& op);
+  void xchg_w(Register reg, const Operand& op);
 
   // Arithmetics
   void adc(Register dst, int32_t imm32);
   void adc(Register dst, const Operand& src);
 
   void add(Register dst, Register src) { add(dst, Operand(src)); }
   void add(Register dst, const Operand& src);
   void add(const Operand& dst, Register src);
   void add(Register dst, const Immediate& imm) { add(Operand(dst), imm); }
   void add(const Operand& dst, const Immediate& x);
@@ skipping 438 matching lines @@
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_X87_ASSEMBLER_X87_H_