Revert Ember.run refactors

This reverts commit 5ca60fcb6b.

test/javascripts/acceptance/composer-test.js.es6

@@ -1,4 +1,3 @@
-import { run } from "@ember/runloop";
 import selectKit from "helpers/select-kit-helper";
 import { acceptance } from "helpers/qunit-helpers";
 import { toggleCheckDraftPopup } from "discourse/controllers/composer";
@@ -85,7 +84,7 @@ QUnit.test("Tests the Composer controls", async assert => {
   event[mac ? "metaKey" : "ctrlKey"] = true;
   event.keyCode = 66;
 
-  run(() => textarea.dispatchEvent(event));
+  Ember.run(() => textarea.dispatchEvent(event));
 
   const example = I18n.t(`composer.bold_text`);
   assert.equal(

test/javascripts/acceptance/modal-test.js.es6

@@ -1,4 +1,3 @@
-import { run } from "@ember/runloop";
 import { acceptance, controllerFor } from "helpers/qunit-helpers";
 import showModal from "discourse/lib/show-modal";
 
@@ -38,7 +37,7 @@ QUnit.test("modal", async function(assert) {
     '{{#d-modal-body title="" class="" dismissable=false}}test{{/d-modal-body}}'
   );
 
-  run(() => showModal("not-dismissable", {}));
+  Ember.run(() => showModal("not-dismissable", {}));
 
   assert.ok(find(".d-modal:visible").length === 1, "modal should appear");