test: make TEST-04 stable once again

Wait a bit if necessary for the cursor file to appear.

Follow-up fb35fea.

(cherry picked from commit 57130ca)

Related: RHEL-30567

test/units/testsuite-04.sh

@@ -186,15 +186,15 @@ set -o pipefail
 
 # https://github.com/systemd/systemd/issues/26746
 rm -f /tmp/issue-26746-log /tmp/issue-26746-cursor
-ID=$(systemd-id128 new)
+ID="$(systemd-id128 new)"
 journalctl -t "$ID" --follow --cursor-file=/tmp/issue-26746-cursor | tee /tmp/issue-26746-log &
 systemd-cat -t "$ID" /bin/sh -c 'echo hogehoge'
 # shellcheck disable=SC2016
 timeout 10 bash -c 'while ! [[ -f /tmp/issue-26746-log && "$(cat /tmp/issue-26746-log)" =~ hogehoge ]]; do sleep .5; done'
 pkill -TERM journalctl
-test -f /tmp/issue-26746-cursor
-CURSOR_FROM_FILE=$(cat /tmp/issue-26746-cursor)
-CURSOR_FROM_JOURNAL=$(journalctl -t "$ID" --output export MESSAGE=hogehoge | sed -n -e '/__CURSOR=/ { s/__CURSOR=//; p }')
+timeout 10 bash -c 'while ! test -f /tmp/issue-26746-cursor; do sleep .5; done'
+CURSOR_FROM_FILE="$(cat /tmp/issue-26746-cursor)"
+CURSOR_FROM_JOURNAL="$(journalctl -t "$ID" --output=export MESSAGE=hogehoge | sed -n -e '/__CURSOR=/ { s/__CURSOR=//; p }')"
 test "$CURSOR_FROM_FILE" = "$CURSOR_FROM_JOURNAL"