Test: Change tests to not rely on "double done" hack

The next commit in this branch for qunitjs#1511, will disallow adding
tests if `QUnit.done()` and `runEnd` have already happened, thus
leading these hacks to fail as follows:

````
Running "qunit:all" (qunit) task
Testing http://localhost:4000/test/index.html
[…]
Testing http://localhost:4000/test/module-skip.html ....
Error: Unexpected new test after the run already ended
    at new Test (http://localhost:4000/qunit/qunit.js:2206:13)
^C
```

In addition, due to a known issue in grunt-contrib-qunit, these would
also indefinitely hack instead of actually failing.

Ref gruntjs/grunt-contrib-qunit#178.
Ref qunitjs#1377.
Ref qunitjs#1511.

Gruntfile.js

@@ -75,9 +75,6 @@ module.exports = function( grunt ) {
 						"test/reorder.html",
 						"test/reorderError1.html",
 						"test/reorderError2.html",
-						"test/callbacks.html",
-						"test/callbacks-promises.html",
-						"test/events.html",
 						"test/events-filters.html",
 						"test/events-in-test.html",
 						"test/logs.html",
@@ -128,7 +125,6 @@ module.exports = function( grunt ) {
 				"test/main/deepEqual.js",
 				"test/main/stack.js",
 				"test/main/utilities.js",
-				"test/events.js",
 				"test/events-in-test.js",
 				"test/onerror/inside-test.js",
 				"test/onerror/outside-test.js",