qapi: New -compat deprecated-input=crash

Policy "crash" calls abort() when deprecated input is received.

Bugs in integration tests may mask the error from policy "reject".
Provide a larger hammer: crash outright.  Masking that seems unlikely.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210318155519.1224118-12-armbru@redhat.com>