Remove jQuery usage from ember-testing

As advised by feedback from core team, this removes all jQuery related testing helpers from ember-testing:
* `find`
* `findWithAssert`
* `triggerEvent`
* `keyEvent`
* `click`
* `fillIn`

All remaining helpers remain untouched for future official deprecation.

packages/ember-testing/index.js

@@ -3,7 +3,6 @@ export { default as Adapter } from './lib/adapters/adapter';
 export { default as setupForTesting } from './lib/setup_for_testing';
 export { default as QUnitAdapter } from './lib/adapters/qunit';
 
-import './lib/support'; // to handle various edge cases
 import './lib/ext/application';
 import './lib/ext/rsvp'; // setup RSVP + run loop integration
 import './lib/helpers'; // adds helpers to helpers object in Test

packages/ember-testing/lib/helpers.js

@@ -1,29 +1,17 @@
 import { registerHelper as helper, registerAsyncHelper as asyncHelper } from './test/helpers';
 import andThen from './helpers/and_then';
-import click from './helpers/click';
 import currentPath from './helpers/current_path';
 import currentRouteName from './helpers/current_route_name';
 import currentURL from './helpers/current_url';
-import fillIn from './helpers/fill_in';
-import find from './helpers/find';
-import findWithAssert from './helpers/find_with_assert';
-import keyEvent from './helpers/key_event';
 import { pauseTest, resumeTest } from './helpers/pause_test';
-import triggerEvent from './helpers/trigger_event';
 import visit from './helpers/visit';
 import wait from './helpers/wait';
 
 asyncHelper('visit', visit);
-asyncHelper('click', click);
-asyncHelper('keyEvent', keyEvent);
-asyncHelper('fillIn', fillIn);
 asyncHelper('wait', wait);
 asyncHelper('andThen', andThen);
 asyncHelper('pauseTest', pauseTest);
-asyncHelper('triggerEvent', triggerEvent);
 
-helper('find', find);
-helper('findWithAssert', findWithAssert);
 helper('currentRouteName', currentRouteName);
 helper('currentPath', currentPath);
 helper('currentURL', currentURL);