Fixes multiple security issues:
* CVE-2022-0667 -- An assertion could occur in resume_dslookup() if the
fetch had been shut down earlier
* CVE-2022-0635 -- Lookups involving a DNAME could trigger an INSIST when
"synth-from-dnssec" was enabled
* CVE-2022-0396 -- A synchronous call to closehandle_cb() caused
isc__nm_process_sock_buffer() to be called recursively,
which in turn left TCP connections hanging in the CLOSE_WAIT
state blocking indefinitely when out-of-order processing was
disabled.
* CVE-2021-25220 -- The rules for acceptance of records into the cache
have been tightened to prevent the possibility of
poisoning if forwarders send records outside the
configured bailiwick
Signed-off-by: Noah Meyerhans <frodo@morgul.net>