Bump to v4.6.0.

_cloneRegExp.js

@@ -9,9 +9,7 @@ var reFlags = /\w*$/;
  * @returns {Object} Returns the cloned regexp.
  */
 function cloneRegExp(regexp) {
-  var Ctor = regexp.constructor,
-      result = new Ctor(regexp.source, reFlags.exec(regexp));
-
+  var result = new regexp.constructor(regexp.source, reFlags.exec(regexp));
   result.lastIndex = regexp.lastIndex;
   return result;
 }