occasionally Windows will randomly decide to deny us access to rename the file for no reason whatsoever. If this happens, we attempt an old-style copy and delete.
If the rename failed for a legit reason, the copy and delete should also fail and generate an error message. If it was Windows being a spaz, it should work normally without errors.
I've stuck to only doing this in the places where I'm sure we should never get false back. Other places I'm less sure of (and I found more bugs along the way).
this fixes many cases of corruption during disk-full situations - file_put_contents() would write an empty file, destroying the original data.
fixes#3152
this is not as good as phpstan/phpstan-src#769 (e.g. array_key_first()/array_key_last() aren't covered by this, nor is array_rand()) but it does eliminate the most infuriating cases where this usually crops up.
this can fail if the backups directory points to a different drive than the original worlds location. In this case, we have to copy and delete the files instead, which is much slower, but works.
I REALLY advise against putting backups on a different mount point than worlds if you plan to convert large worlds.
