Move regexp implementation into its own folder.

src/regexp/regexp-macro-assembler.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_REGEXP_MACRO_ASSEMBLER_H_
-#define V8_REGEXP_MACRO_ASSEMBLER_H_
+#ifndef V8_REGEXP_REGEXP_MACRO_ASSEMBLER_H_
+#define V8_REGEXP_REGEXP_MACRO_ASSEMBLER_H_
 
 #include "src/ast.h"
 
 namespace v8 {
 namespace internal {
 
 struct DisjunctDecisionRow {
   RegExpCharacterClass cc;
   Label* on_match;
 };
@@ skipping 223 matching lines @@
                         const byte* input_end,
                         int* output,
                         int output_size,
                         Isolate* isolate);
 };
 
 #endif  // V8_INTERPRETED_REGEXP
 
 } }  // namespace v8::internal
 
-#endif  // V8_REGEXP_MACRO_ASSEMBLER_H_
+#endif  // V8_REGEXP_REGEXP_MACRO_ASSEMBLER_H_