Clean up some things I noticed while doing another change (#45658)

This fixes some minor things I noticed while doing another change.

- Uncomments an old test that wants to be run, but can't be, and marked it as "skipped", so that the code won't rot anymore.
- Added the focus state to the short string version of a FocusNode
- Added a missing piece of information to findAncestorWidgetOfExactType