test: term: When checking if status line is a number, hide errors

We use the [ "$x" -eq "$x" ] syntax to check if $x is a number. The
behaviour is clearly implied by POSIX, but some shells might actually
report the (intended) error, and dash floods script.log with
"Illegal number" error messages. Hide them.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

test/lib/term

@@ -232,7 +232,7 @@ pane_status() {
 	[ ${DEMO} -eq 1 ] && return 0
 
 	__status="$(pane_parse "${1}")"
-	while ! [ "${__status}" -eq "${__status}" ]; do
+	while ! [ "${__status}" -eq "${__status}" ] 2>/dev/null; do
 		sleep 1
 		pane_run "${1}" 'echo $?'
 		pane_wait "${1}"