ts_recovery-itest flaky since KUDU-1034 fixed

ts_recovery-itest is quite flaky lately (~50% in TSAN builds). I was able to reproduce the flakiness reliably doing:

taskset -c 0-1 ./build-support/run-test.sh ./build/latest/bin/ts_recovery-itest --gtest_filter=\*Orphan\* -stress-cpu-threads 4

I tracked the flakiness down to being introduced by KUDU-1034 (4263b037844fca595a35f99479fbb5765ba7a443). The issue seems to be that the test sets a low timeout such that a large number of requests time out, and with the new behavior introduced by that commit, we end up hammering the master and unable to make progress.

Unclear if this is a feature (and we need to update the test) or a bug