When cd is passed a broken symlink, this changes the error message from
"no such directory" to "broken symbolic link". This scenario probably
won't happen very often since completion won't suggest broken symlinks
but it can't hurt to give a good error.
Fish used to do this until 7ac5932. This logic used to be in
path_get_cdpath, however, that is only used for highlighting, so we
don't need error messages there. Changing cd is enough.
Reword from "rotten" to "broken" since that's what file(1) uses.
Clean-up leftovers from old "rotten" code (nomen est omen).
See #8264
Solaris/OpenIndiana/Illumos `rm` checks that and errors out.
In these cases we don't actually need it to be a part of $PWD as
it's just for cleanup, so we `cd` out before.
See #5472
See 1ee57e9244Fixes#6555Fixes#6558
macOS `mktemp -d` likes to return symlinks. Guard against that possibility.
That allows the test to succeed when run directly, instead of through the
build target.
