Disabling flaky tests: https://chromium-review.googlesource.com/c/chromium/src/+/1379209

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b145bbabbaae4e639d70b9f217a8d572f29202f0

commit b145bbabbaae4e639d70b9f217a8d572f29202f0
Author: Hongchan Choi <hongchan@chromium.org>
Date: Sat Dec 15 00:38:52 2018

Disable TwoClientPasswordsSyncTest.SetPassphraseAndAddPassword (flaky)

TBR=hans

Bug:  915383 
Change-Id: If4e475852268863bc2f854cfeb7c253ebf8b348d
Reviewed-on: https://chromium-review.googlesource.com/c/1379209
Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Hongchan Choi <hongchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616899}
[modify] https://crrev.com/b145bbabbaae4e639d70b9f217a8d572f29202f0/chrome/browser/sync/test/integration/two_client_passwords_sync_test.cc

Other TwoClientPasswordsSyncTests are also failing on TSan bot.
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=sync_integration_tests&tests=TwoClientPasswordsSyncTest

In my read of this log, the failure seems happening due to a read of FeatureList on IO thread while it's written on the main thread in the test.
https://chromium-swarm.appspot.com/task?id=41d28b7eec766c10&refresh=10&show_raw=1

I think we need to setup the feature flag before getting the test body started, as  https://crbug.com/915219#c7  mentioned.
https://cs.chromium.org/chromium/src/chrome/browser/sync/test/integration/two_client_passwords_sync_test.cc?type=cs&q=TwoClientPasswordsSyncTest&sq=package:chromium&g=0&l=60