Port better to NFS unlink

Port better to NFS unlink

I found this problem while looking into Bug#72641.
* lib-src/etags.c (do_move_file):
* lib-src/update-game-score.c (unlock_file):
* src/androidvfs.c (android_hack_asset_fd_fallback):
* src/filelock.c (current_lock_owner):
Treat unlink as successful if it fails because the file wasn’t there.
This can happen with some NFS implementations, due to its
retrying over the network to get at-least-once semantics.
Although most of Emacs’s calls to unlink were already doing this,
a few instances were not.

(cherry picked from commit 40eecd594ac60f38b6729fd9cf3474a8b9d133b9)