Remove fallback to $wgUser in LocalRepo::findFiles(), FileRepo::findFiles(), and FileRepo::findFileFromKey().
These were added in 5e703cdf669f85e2924dee76c5a8831633259ce0 as a hacky backport patch to fix T263014 and properly deprecate a missing hard-deprecation in File::canUser. But it should be fixed properly in 1.36.