test: reset systemd-resolved.service's restart counter

Otherwise we might occasionally hit the start rate limit, as we restart
the service a bunch of times:

[ 3702.280886] testsuite-75.sh[1135]: + tee /tmp/tmp.wUL8bkJwrt
[ 3702.283684] testsuite-75.sh[1135]: {}
[ 3702.284254] testsuite-75.sh[46]: + restart_resolved
[ 3702.284302] testsuite-75.sh[46]: + systemctl stop systemd-resolved.service
[ 3702.310678] testsuite-75.sh[1140]: + systemctl is-failed systemd-resolved.service
[ 3702.316766] testsuite-75.sh[1141]: inactive
[ 3702.316998] testsuite-75.sh[46]: + systemctl start systemd-resolved.service
[ 3702.322315] systemd[1]: systemd-resolved.service: Start request repeated too quickly.
[ 3702.322343] systemd[1]: systemd-resolved.service: Failed with result 'start-limit-hit'.
[ 3702.322609] systemd[1]: Failed to start systemd-resolved.service - Network Name Resolution.
[ 3702.323619] systemctl[1142]: Job for systemd-resolved.service failed.
[ 3702.323839] systemctl[1142]: See "systemctl status systemd-resolved.service" and "journalctl -xeu systemd-resolved.service" for details.
[ 3702.325035] systemd[1]: testsuite-75.service: Failed with result 'exit-code'.
[ 3702.325391] systemd[1]: Failed to start testsuite-75.service - Tests for systemd-resolved.

Follow-up for b1384db and 6ef512c.

(cherry picked from commit 68785c7)
(cherry picked from commit 5cd1792)

Author: mrc0mmand

test/units/testsuite-75.sh

@@ -46,6 +46,9 @@ monitor_check_rr() (
 restart_resolved() {
     systemctl stop systemd-resolved.service
     (! systemctl is-failed systemd-resolved.service)
+    # Reset the restart counter since we call this method a bunch of times
+    # and can occasionally hit the default rate limit
+    systemctl reset-failed systemd-resolved.service
     systemctl start systemd-resolved.service
     systemctl service-log-level systemd-resolved.service debug
 }