attempt to reset hardware before each test (#859)

* Trims SSD drives, flushes cache before each performance test. Unfortunately these are still incomplete -- need to use real hardware machines for all these to take effect.
* A bit more output in PR updater

.github/workflows/pr-updater.yml

@@ -88,6 +88,7 @@ jobs:
             exit
           else
             echo "$PR_COUNT pull requests have been updated in the last $IGNORE_PRS_OLDER_THAN minutes"
+            echo "$PULL_REQUESTS" | jq -r 'keys|.[]|" * " + .'
           fi