override Dir#mktmpdir to force-sanitize prefix_suffix

on windows the allowed characters for directories is stricter than on posix
and as a result self.class may not be used as prefix verbatim.
as a safe guard we now prepend a sanitizer to Dir#mktmpdir so that only
valid characters can be used as prefix_suffix and we wont accidently create
invalid paths in the future

BUG: 393011