quick fix for flaky TestMixerReportingToMixer (#4886)
quick fix for flaky TestMixerReportingToMixer (#4886)

Automatic merge from submit-queue.

quick fix for flaky TestMixerReportingToMixer

TestMixerReportingToMixer searches pod logs to verify mixer is
reporting on itself. The current code checks the last 100 lines of
logs which may not be sufficient to capture enough report
history. Increase the search to the last 1000 lines as a quick fix for
postsubmit failures.

fixes https://github.com/istio/istio/issues/4858
smawson/istio,geeknoid/istio,frankbu/istio,istio/istio,istio/istio,frankbu/istio,istio/istio,geeknoid/istio,frankbu/istio,smawson/istio,istio/istio,geeknoid/istio,geeknoid/istio,frankbu/istio,frankbu/istio,istio/istio,smawson/istio,frankbu/istio,geeknoid/istio,smawson/istio,geeknoid/istio,smawson/istio,smawson/istio