torture: Compress KCSAN as well as KASAN vmlinux files

Compressing KASAN vmlinux files reduces torture.sh res file size from
about 100G to about 50G, which is good, but the KCSAN vmlinux files
are also large.  Compressing them reduces their size from about 700M to
about 100M (but of course your mileage may vary).  This commit therefore
compresses both KASAN and KCSAN vmlinux files.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>