As said in the warning after #21659, a set of ints defaults to
`set[range[0..65535]]` which is very large. So in osproc, a `case`
statement is used instead of an int set to check for an int being one of
2 values.
Also tested all of CI with the warning from #21659 as an error, this
seems to be the only remaining case in CI.
(cherry picked from commit 706985997e)
0fde5a0cc2