[Sheriff] Disable flaky test PlatformThreadTest

Disable PlatformThreadTest.SetCurrentThreadPriorityWithThreadModeBackground
and PlatformThreadTest.SetCurrentThreadPriorityWithThreadModeBackgroundIdleProcess
(these tests are Windows-only).

Bug: 931706
TBR=fdoray@chromium.org

Change-Id: I996a7faff6afc4ac161ec863a4a320e79f2a18c9
Reviewed-on: https://chromium-review.googlesource.com/c/1471016
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#631860}
1 file changed