test: bump the container spawn timeout to 60s

As 30s might be not enough on busy systems (and we already bumped the
reboot timeout from 30s to 60s for this reason).

(cherry picked from commit d932022ddfe021b1c49ffaf4d7dfe4093656f0c5)
(cherry picked from commit c2fef536d5d2f588c93159d7cf7cb83016dda2ef)

test/test-shutdown.py

@@ -16,7 +16,7 @@ def run(args):
     logger.info("spawning test")
     console = pexpect.spawn(args.command, args.arg, env={
             "TERM": "linux",
-        }, encoding='utf-8', timeout=30)
+        }, encoding='utf-8', timeout=60)
 
     if args.verbose:
         console.logfile = sys.stdout