MFC r340272, r340274, r340294

r340272:
Make __sysctl follow the freebsd32_foo convention.

Sponsored by: DARPA, AFRL

r340274:
Make freebsd32_umtx_op follow the freebsd32_foo convention.

Sponsored by: DARPA, AFRL

r340294:
Fix a number of bugs in freebsd32's capabilities.conf.

Bugs range from failure to update after changing syscall implementaion
names to using the wrong name. Somewhat confusingly, the name in
capabilities.conf is exactly the string that appears in syscalls.master,
not the name with a COMPAT* prefix which is the actual function name.

Found while making a change to use the default capabilities.conf.

Fixes: r335177, r336980, r340272, r340274, others
Reviewed by: kib, emaste
Approved by: re (gjb)
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D17925