Resolve "dns_message_checksig under oss_fuzz is not seeing the data files" [v9_18]
Access to the source tree is not available with oss_fuzz. Have fuzz/dns_message_checksig build and populate a key directory for the fuzzer to use. This contains a key pair and a zone file which has the public key from the key pair. Clean it up on shutdown.
(cherry picked from commit 033057ba)
Closes #3569 (closed)
Edited by Mark Andrews