Extend the "tsiggss" system test with reproducers for CVE-2020-8625 and CVE-2021-25216.
NOTE: This MR cannot be merged at the moment (see a discussion
elsewhere for context) - it needs to wait until ASAN-enabled CI
jobs are moved to Fedora 38, which is expected to happen around May
Moved from isc-private/bind9!287
Closes #2354 (closed)