Disable promise_test

These promise-based tests all flake on IE. E.g., https://travis-ci.org/google/closure-library/builds/108424512.

Author: joeltine

protractor_spec.js

@@ -16,7 +16,8 @@ var IGNORED_TESTS = [
   'closure/goog/testing/fs/integration_test.html',
   'closure/goog/debug/fpsdisplay_test.html',
   'closure/goog/net/jsloader_test.html',
-  'closure/goog/net/filedownloader_test.html'
+  'closure/goog/net/filedownloader_test.html',
+  'closure/goog/promise/promise_test.html'
 ];
 
 describe('Run all Closure unit tests', function() {