[9.16] Build FreeBSD with MIT Kerberos5 instead of Heimdal

tsiggss system tests crash or are unstable with the base FreeBSD (Heimdal-based) GSS-API.

Move the --without-gssapi ./configure option to Alpine Linux, so the option is tested somewhere.

(cherry picked from commit d6df757f)

Backport of MR !8906 (merged).