torture: Remove "Failed to add ttynull console" false positive

Commit 757055ae ("init/console: Use ttynull as a fallback when
there is no console") results in the string "Warning: Failed to add
ttynull console. No stdin, stdout, and stderr for the init process!"
appearing on the console, which the rcutorture scripting interprets as
a warning, which causes every rcutorture run to be flagged.  However,
the rcutorture init process never attempts to do any I/O, and thus does
not care that it has no stdin, stdout, or stderr.

This commit therefore causes the rcutorture scripting to ignore this
message.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/testing/selftests/rcutorture/bin/console-badness.sh

@@ -14,4 +14,5 @@ egrep 'Badness|WARNING:|Warn|BUG|===========|Call Trace:|Oops:|detected stalls o
 grep -v 'ODEBUG: ' |
 grep -v 'This means that this is a DEBUG kernel and it is' |
 grep -v 'Warning: unable to open an initial console' |
+grep -v 'Warning: Failed to add ttynull console. No stdin, stdout, and stderr.*the init process!' |
 grep -v 'NOHZ tick-stop error: Non-RCU local softirq work is pending, handler'

tools/testing/selftests/rcutorture/bin/parse-console.sh

@@ -128,7 +128,7 @@ then
 	then
 		summary="$summary  Badness: $n_badness"
 	fi
-	n_warn=`grep -v 'Warning: unable to open an initial console' $file | egrep -c 'WARNING:|Warn'`
+	n_warn=`grep -v 'Warning: unable to open an initial console' $file | grep -v 'Warning: Failed to add ttynull console. No stdin, stdout, and stderr for the init process' | egrep -c 'WARNING:|Warn'`
 	if test "$n_warn" -ne 0
 	then
 		summary="$summary  Warnings: $n_warn"