torture: Drop trailing ^M from console output

torture: Drop trailing ^M from console output

Console logs can sometimes have trailing control-M characters, which the
forward-progress evaluation code in kvm-recheck-rcu.sh passes through
to the user output.  Which does not cause a technical problem, but which
can look ugly.  This commit therefore strips the control-M characters.

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