torture: Remove RCU_FAST_NO_HZ from rcuscale and refscale scenarios

All of the rcuscale and refscale scenarios that mention the Kconfig option
CONFIG_RCU_FAST_NO_HZ disable it.  But this Kconfig option is disabled by
default, so this commit removes the pointless "CONFIG_RCU_FAST_NO_HZ=n"
lines from these scenarios.

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