bug#49905: xref-find-references doesn't change directory to match relative filenames

[Juri Linkov]

>> 3. check that default-directory of the output*xref*  buffer
>>     with relative file names is not project's root.
>
> But does that lead to you not being able to visit the references by
> pressing RET (or C-o)?

No problem with RET and C-o, but e.g. using 'find-file-at-point'
on the file name fails to find the relative file name.