Disable SystemLogUploaderTest.LogThrottleTest

This test was very flaky on linux-chromeos-dbg.

Bug: 1022591
Change-Id: I9b306c9a426432f87688cffedb3460e254f4f77c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1903818Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713735}

chrome/browser/chromeos/policy/system_log_uploader_unittest.cc

@@ -295,10 +295,11 @@ class SystemLogUploaderTest : public testing::TestWithParam<bool> {
   base::HistogramTester histogram_tester_;
 };
 
+// TODO(crbug.com/1022591) Disabled because of flakiness.
 // Verify log throttling. Try successive kLogThrottleCount log uploads by
 // creating a new task. First kLogThrottleCount logs should have 0 delay.
 // Successive logs should have approx. kLogThrottleWindowDuration delay.
-TEST_P(SystemLogUploaderTest, LogThrottleTest) {
+TEST_P(SystemLogUploaderTest, DISABLED_LogThrottleTest) {
   for (int upload_num = 0;
        upload_num < SystemLogUploader::kLogThrottleCount + 3; upload_num++) {
     EXPECT_FALSE(task_runner_->HasPendingTask());