Bug 855771: Disable tab-utils test for frequent intermittent failures.

Author: Mossop

addon-sdk/source/test/test-tab-utils.js

@@ -67,4 +67,7 @@ else if (isTabPBSupported) {
   };
 }
 
+// Test disabled because of bug 855771
+module.exports = {};
+
 require('test').run(exports);