Attempt to make \b\w+ faster. Slight performance increase on, e.g., string unpacking.

src/x64/regexp-macro-assembler-x64.h

 // Copyright 2009 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 55 matching lines @@
                                          uint32_t mask,
                                          Label* on_not_equal);
   virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
                                               uc16 minus,
                                               uc16 mask,
                                               Label* on_not_equal);
   // Checks whether the given offset from the current position is before
   // the end of the string.
   virtual void CheckPosition(int cp_offset, Label* on_outside_input);
   virtual bool CheckSpecialCharacterClass(uc16 type,
-                                          int cp_offset,
-                                          bool check_offset,
                                           Label* on_no_match);
   virtual void Fail();
   virtual Handle<Object> GetCode(Handle<String> source);
   virtual void GoTo(Label* label);
   virtual void IfRegisterGE(int reg, int comparand, Label* if_ge);
   virtual void IfRegisterLT(int reg, int comparand, Label* if_lt);
   virtual void IfRegisterEqPos(int reg, Label* if_eq);
   virtual IrregexpImplementation Implementation();
   virtual void LoadCurrentCharacter(int cp_offset,
                                     Label* on_end_of_input,
@@ skipping 197 matching lines @@
   Label exit_label_;
   Label check_preempt_label_;
   Label stack_overflow_label_;
 };
 
 #endif  // V8_NATIVE_REGEXP
 
 }}  // namespace v8::internal
 
 #endif  // V8_X64_REGEXP_MACRO_ASSEMBLER_X64_H_