Build: dependencies: Update optional testing dependencies

cts-exec and cts-fencing are written in Python and thus no longer
require procps or psmisc.

There are no valgrind tests in CTS lab. See a58a4000.

cts-* scripts import from files in python/pacemaker/_cts that eventually
import from python/pacemaker/_cts/process.py, which imports psutil.

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>