Add fast paths for native RegExps in ES2015 subclass-aware code

src/js/harmony-unicode-regexps.js

Index: src/js/harmony-unicode-regexps.js
diff --git a/src/js/harmony-unicode-regexps.js b/src/js/harmony-unicode-regexps.js
index b24bbdf2c545975c7455588ebc5df7c902139716..fcee6581d73a7f24fdb22756c47ec26eadbd7ecf 100644
--- a/src/js/harmony-unicode-regexps.js
+++ b/src/js/harmony-unicode-regexps.js
@@ -33,8 +33,7 @@ function RegExpGetUnicode() {
   }
   return !!REGEXP_UNICODE(this);

[Dan Ehrenberg, 2016/03/28 22:56:09]

While making a change here, maybe change to TO_BOOLEAN, here and in the other
flag getters?

[adamk, 2016/03/28 23:14:37]

Done.

 }
-%FunctionSetName(RegExpGetUnicode, "RegExp.prototype.unicode");
-%SetNativeFlag(RegExpGetUnicode);
+%SetForceInlineFlag(RegExpGetUnicode);
 
 utils.InstallGetter(GlobalRegExp.prototype, 'unicode', RegExpGetUnicode);