[v9_11] Use SIGABRT instead of SIGKILL to produce cores on failed start
When the named
would hang on startup it would be killed with SIGKILL
leaving us with no information about the state the process was in.
This commit changes the start.pl script to send SIGABRT instead, so we
can properly collect and process the coredump from the hung named
process.
(cherry picked from commit 861a2369)