A real life scenario is that cores are compressed to reduce
size of dumpon partition, but we either don't care about space
in the /var/crash or we have a filesystem level compression of
/var/crash. And we want cores to be uncompressed in /var/crash
because we'd like to instantily read them with kgdb.
In this case we want kernel to write cores compressed, but
savecore(1) write them uncompressed.