Auto merge of #121372 - clubby789:test-all-tests, r=onur-ozkan

Make `x test tests` work

Fixes #97314

This makes `x test tests` work, and be roughly equivalent to `x test tests/*`. The `--dry-run` output is identical, except for errors on the non-test items in `tests` and a couple of things being in a different order (where path != struct name).

This probably needs a test, but I'm not sure of the best way to do it.

Author: bors