[regexp] do not include irregexp interpreter by default.

src/regexp/regexp-macro-assembler-irregexp.cc

Index: src/regexp/regexp-macro-assembler-irregexp.cc
diff --git a/src/regexp/regexp-macro-assembler-irregexp.cc b/src/regexp/regexp-macro-assembler-irregexp.cc
index 751ee441c82d3aed5f9185b938cc2bb9434332ec..c2af23fc312ff97d45018997c4f78b071dc61246 100644
--- a/src/regexp/regexp-macro-assembler-irregexp.cc
+++ b/src/regexp/regexp-macro-assembler-irregexp.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#ifdef V8_INTERPRETED_REGEXP
+
 #include "src/regexp/regexp-macro-assembler-irregexp.h"
 
 #include "src/ast/ast.h"
@@ -9,12 +11,9 @@
 #include "src/regexp/regexp-macro-assembler.h"
 #include "src/regexp/regexp-macro-assembler-irregexp-inl.h"
 
-
 namespace v8 {
 namespace internal {
 
-#ifdef V8_INTERPRETED_REGEXP
-
 RegExpMacroAssemblerIrregexp::RegExpMacroAssemblerIrregexp(Isolate* isolate,
                                                            Vector<byte> buffer,
                                                            Zone* zone)
@@ -454,7 +453,7 @@ void RegExpMacroAssemblerIrregexp::Expand() {
   }
 }
 
-#endif  // V8_INTERPRETED_REGEXP
-
 }  // namespace internal
 }  // namespace v8
+
+#endif  // V8_INTERPRETED_REGEXP