After upgrading Qunit from 4.4.1 to 5.1.5, willDestroyElement no longer runs after acceptance test finishes

[andrew-paterson]

This might be a duplicate of #332, but that issue is locked.

My Ember version is 3.12.0, and Node is 12.16.3.

In Qunit 5.1.5, the component willDestroyElement hook is not called when an acceptance test finishes.
In Qunit 4.4.1 it did fire.

I've created a repo which reproduces the behaviour: https://github.com/andrew-paterson/qunit-bug

There is a commit labelled Qunit 4.4.1 and another labelled Qunit 5.1.5. There is a single component which logs to the console in the willDestroyElement hook.

The single acceptance test module has 2 tests, which result in two firings of the component's willDestroyElement hook with Qunit 4.4.1. However, the same tests does not result in the same with Qunit 5.1.5.