remove most uses of Isolate::Current in arch specific files

src/x64/code-stubs-x64.h

 // Copyright 2011 the V8 project authors. 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.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 51 matching lines @@
 };
 
 
 class StoreBufferOverflowStub: public PlatformCodeStub {
  public:
   explicit StoreBufferOverflowStub(SaveFPRegsMode save_fp)
       : save_doubles_(save_fp) { }
 
   void Generate(MacroAssembler* masm);
 
-  virtual bool IsPregenerated() { return true; }
+  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE { return true; }
   static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);
   virtual bool SometimesSetsUpAFrame() { return false; }
 
  private:
   SaveFPRegsMode save_doubles_;
 
   Major MajorKey() { return StoreBufferOverflow; }
   int MinorKey() { return (save_doubles_ == kSaveFPRegs) ? 1 : 0; }
 };
 
@@ skipping 231 matching lines @@
               address,  // An input reg.
               value) {  // One scratch reg.
   }
 
   enum Mode {
     STORE_BUFFER_ONLY,
     INCREMENTAL,
     INCREMENTAL_COMPACTION
   };
 
-  virtual bool IsPregenerated();
+  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE;
   static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);
   virtual bool SometimesSetsUpAFrame() { return false; }
 
   static const byte kTwoByteNopInstruction = 0x3c;  // Cmpb al, #imm8.
   static const byte kTwoByteJumpInstruction = 0xeb;  // Jmp #imm8.
 
   static const byte kFiveByteNopInstruction = 0x3d;  // Cmpl eax, #imm32.
   static const byte kFiveByteJumpInstruction = 0xe9;  // Jmp #imm32.
 
   static Mode GetMode(Code* stub) {
@@ skipping 199 matching lines @@
   RememberedSetAction remembered_set_action_;
   SaveFPRegsMode save_fp_regs_mode_;
   Label slow_;
   RegisterAllocation regs_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_CODE_STUBS_X64_H_