The `FIND_LIBRARY_USE_LIB<arch>_PATHS` global properties ask
`find_library` to look in `lib<arch>` directories automatically before
corresponding `lib` directories. However, if `lib<arch>` is just a
symlink to `lib` (or vice-versa) then we should skip adding the
`lib<arch>` path. Such symlinks typically only exist to satisfy
software that expects the `lib<arch>` path to be available.
Fixes: #16687