Revert of [regexp] restrict pattern syntax for unicode mode.

src/regexp/regexp-parser.h

Index: src/regexp/regexp-parser.h
diff --git a/src/regexp/regexp-parser.h b/src/regexp/regexp-parser.h
index b7dfb4875fe071a3d4ee12b47569f47fad1ac35f..3b2a2f68807543f46b183ee0a0bbc08eff3410d3 100644
--- a/src/regexp/regexp-parser.h
+++ b/src/regexp/regexp-parser.h
@@ -111,7 +111,7 @@
   void AddTerm(RegExpTree* tree);
   void AddAssertion(RegExpTree* tree);
   void NewAlternative();  // '|'
-  bool AddQuantifierToAtom(int min, int max,
+  void AddQuantifierToAtom(int min, int max,
                            RegExpQuantifier::QuantifierType type);
   RegExpTree* ToRegExp();
 
@@ -198,7 +198,7 @@
   bool unicode() const { return (flags_ & JSRegExp::kUnicode) != 0; }
   bool multiline() const { return (flags_ & JSRegExp::kMultiline) != 0; }
 
-  static bool IsSyntaxCharacterOrSlash(uc32 c);
+  static bool IsSyntaxCharacter(uc32 c);
 
   static const int kMaxCaptures = 1 << 16;
   static const uc32 kEndMarker = (1 << 21);