Avoid piping send directly to /dev/null

Unfortunately, #11445 means while we fail gracefully now, we still
fail, unless people want to implement a complex workaround just to
support /dev/null.

So let's just use the cheap workaround in a test for now.

Signed-off-by: Rich Ercolani <rincebrain@gmail.com>

tests/zfs-tests/tests/functional/history/history_006_neg.ksh

@@ -75,7 +75,8 @@ if ! is_linux; then
 	log_must zfs share $fs
 	log_must zfs unshare $fs
 fi
-log_must zfs send -i $snap1 $snap2 > /dev/null
+# https://github.com/openzfs/zfs/issues/11445
+log_must zfs send -i $snap1 $snap2 | cat > /dev/null
 log_must zfs holds $snap1
 
 log_must eval "zpool history $TESTPOOL > $NEW_HISTORY"