Update Firefox pretty print test

At some point, firefox changed the exception message.

spec/javascripts/html/PrettyPrintHtmlSpec.js

@@ -9,7 +9,7 @@ describe("j$.pp (HTML Dependent)", function () {
   it("should print Firefox's wrapped native objects correctly", function() {
     if(jasmine.getEnv().firefoxVersion) {
       try { new CustomEvent(); } catch(e) { var err = e; };
-      expect(j$.pp(err)).toMatch(/Exception.*Not enough arguments/);
+      expect(j$.pp(err)).toMatch(/Not enough arguments/);
     }
   });
 });