Rollup merge of #152888 - ValorZard:async-drop-fix, r=oli-obk

Fix async drop glue MIR bug

Attempted to fix rust-lang/rust#142560
Relevant Zulip (where I talk a lot more about what I did): [#wg-async > is there a way I can help with Async Drop?](https://rust-lang.zulipchat.com/#narrow/channel/187312-wg-async/topic/is.20there.20a.20way.20I.20can.20help.20with.20Async.20Drop.3F/with/572847292)

Author: JonathanBrouwer