Remove use of Isolate::Current in regexp macro assemblers.

src/regexp-macro-assembler-irregexp.h

 // Copyright 2012 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 116 matching lines @@
   // The program counter.
   int pc_;
   // True if the assembler owns the buffer, false if buffer is external.
   bool own_buffer_;
   Label backtrack_;
 
   int advance_current_start_;
   int advance_current_offset_;
   int advance_current_end_;
 
+  Isolate* isolate_;
+
   static const int kInvalidPC = -1;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(RegExpMacroAssemblerIrregexp);
 };
 
 #endif  // V8_INTERPRETED_REGEXP
 
 } }  // namespace v8::internal
 
 #endif  // V8_REGEXP_MACRO_ASSEMBLER_IRREGEXP_H_