main/busybox: backport ed and ash fixes

See:

• http://lists.busybox.net/pipermail/busybox/2022-February/089490.html
• http://lists.busybox.net/pipermail/busybox/2022-January/089439.html
• http://lists.busybox.net/pipermail/busybox/2022-February/089446.html

Ideally, I would like to wait until all of these patches are reviewed & merged upstream. However, Denys is probably busy with other things at the moment. Therefore, I suggest we just push these for now and follow-up later.

Fixes #13469 (closed)

Fixes #13504 (closed)

See also: #13560 (closed)