Disable DeskTraversalNonTouchpadMetrics due to flakiness.

TBR=sammiequon@chromium.org

Bug: 1163489
Change-Id: Id7522dc2da9562b970249b4ab976ccccd31a3ec9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2613044Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840567}

ash/wm/desks/desks_unittests.cc

@@ -3705,7 +3705,8 @@ class DesksMockTimeTest : public AshTestBase {
   ~DesksMockTimeTest() override = default;
 };
 
-TEST_F(DesksMockTimeTest, DeskTraversalNonTouchpadMetrics) {
+// crbug.com/1163489
+TEST_F(DesksMockTimeTest, DISABLED_DeskTraversalNonTouchpadMetrics) {
   NewDesk();
   NewDesk();
   NewDesk();