fix: dev: Fix the resesuid() shim implementation for NetBSD

The shim implementation of setresuid() was wrong - there was a copy and
paste error and it was calling setresgid() instead.  This only affects
NetBSD because Linux, FreeBSD and OpenBSD have setresuid() and
setresgid() implementation available from the system library.

Closes #4862

Merge branch '4862-fix-setresuid-shim' into 'main'

Closes #4862

See merge request isc-projects/bind9!9359