Tweak timings in serve-stale system test

Give a little bit more time if we wait on a time out from the
authoritative (aka resolver failure), and give up after one try
(because the second attempt will likely result in a different EDE).

(cherry picked from commit f764cee1)
68 jobs for !6350 with 3341-servestale-extendederrors-test-failure-v9_18 in 33 minutes and 48 seconds (queued for 8 seconds)
Name Stage Failure
system:gcc:asan System There has been a missing dependency failure
No job log