Revert "Rename all test files from JS -> ES6"

This reverts commit 2abe85b8344de1102c1589a9ac9421a8b296f2b5.

test/javascripts/lib/load-script-test.js

@@ -1,21 +0,0 @@
-import loadScript from "discourse/lib/load-script";
-
-QUnit.module("lib:load-script");
-
-QUnit.skip(
-  "load with a script tag, and callbacks are only executed after script is loaded",
-  async assert => {
-    assert.ok(
-      typeof window.ace === "undefined",
-      "ensures ace is not previously loaded"
-    );
-
-    const src = "/javascripts/ace/ace.js";
-
-    await loadScript(src);
-    assert.ok(
-      typeof window.ace !== "undefined",
-      "callbacks should only be executed after the script has fully loaded"
-    );
-  }
-);