simpler regexp for js identifiers

non identifier chars in \u00a1-\uffff range are errors anyway
   so they can be highlighted either as operator or as identifier
   using this instead of detailed unicode regexps reduces parse time
   by ~3x, and gives the same result for any valid js

lib/ace/mode/javascript_highlight_rules.js

@@ -93,11 +93,7 @@ var JavaScriptHighlightRules = function() {
     );
 
     // TODO: Unicode escape sequences
-    var identifierRe = "[" + unicode.packages.L + "\\$_]["
-        + unicode.packages.L
-        + unicode.packages.Mn + unicode.packages.Mc
-        + unicode.packages.Nd
-        + unicode.packages.Pc + "\\$_]*\\b";
+    var identifierRe = "[a-zA-Z\\$_\u00a1-\uffff][a-zA-Z\d\\$_\u00a1-\uffff]*\\b";
 
     var escapedRe = "\\\\(?:x[0-9a-fA-F]{2}|" + // hex
         "u[0-9a-fA-F]{4}|" + // unicode