Prevent ReDoS

To fix https://github.com/lodash/lodash/issues/3359, modified reHasUnicodeWord to remove an unnecessary comma which made the regex greedy, this is only a test regex and not a matching regex. Added unit tests, this now should run under 5 ms instead of over 1000 ms for huge 50k+ char words.

lodash.js

@@ -276,7 +276,7 @@
   var reHasUnicode = RegExp('[' + rsZWJ + rsAstralRange  + rsComboRange + rsVarRange + ']');
 
   /** Used to detect strings that need a more robust regexp to match words. */
-  var reHasUnicodeWord = /[a-z][A-Z]|[A-Z]{2,}[a-z]|[0-9][a-zA-Z]|[a-zA-Z][0-9]|[^a-zA-Z0-9 ]/;
+  var reHasUnicodeWord = /[a-z][A-Z]|[A-Z]{2}[a-z]|[0-9][a-zA-Z]|[a-zA-Z][0-9]|[^a-zA-Z0-9 ]/;
 
   /** Used to assign default `context` object properties. */
   var contextProps = [