named segfaults after a call to dns_name_equal

Issue

• named crashes. Coredump shows an assertion error (isc_assertion_failed) right after a call to dns_name_equal.

                Stack trace of thread 215268:
                #0  0x00007fbb0d8a154c __pthread_kill_implementation (libc.so.6 + 0xa154c)
                #1  0x00007fbb0d854d06 raise (libc.so.6 + 0x54d06)
                #2  0x00007fbb0d8287f3 abort (libc.so.6 + 0x287f3)
                #3  0x000055787c9c15b5 assertion_failed.cold (named + 0x1c5b5)
                #4  0x00007fbb0e65d420 isc_assertion_failed (libisc-9.16.23-RH.so + 0x1c420)
                #5  0x00007fbb0e49f9ca dns_name_equal (libdns-9.16.23-RH.so + 0x9f9ca)
                #6  0x00007fbb0e4b48ec dns_order_find (libdns-9.16.23-RH.so + 0xb48ec)
                #7  0x00007fbb0e749de8 query_addrrset.lto_priv.0 (libns-9.16.23-RH.so + 0x1dde8)
                #8  0x00007fbb0e74eece query_gotanswer (libns-9.16.23-RH.so + 0x22ece)