[dashboard] Skip flaky ListTestSuitesTest.testPartialTestSuites
[dashboard] Skip flaky ListTestSuitesTest.testPartialTestSuites

TBR=simonhatch@chromium.org,benjhayden@chromium.org

Bug: chromium:860103
Change-Id: I7a7f7092ab7a616fecf728b47fa82736876ccf6e
Reviewed-on: https://chromium-review.googlesource.com/1125920
Reviewed-by: Juan Antonio Navarro Pérez <1649bb5e6b9eafe026580e338065dc64ba6b80b2@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <1649bb5e6b9eafe026580e338065dc64ba6b80b2@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult