What is the bug or feature:
Why don't all flaky tests appear in the list?

Context or examples:
In issue 887736 I noted that some tests appear in the list due to what appears to be a shard failure. However, not all the 291 tests that "failed" show up in the flaky tests list (list from [1]). In particular, I searched for the first 5 tests reported as failing in that run:
  WebRtcInternalsBrowserTest.ConvertedGraphs
  SitePerProcessBrowserTest.FrameDepthSimple
  WakeLockTest.UnlockAfterTabCrashed
  RenderFrameHostManagerTest.PopupKeepsWindowReferenceCrossProcesAndBack
  WebRtcDataBrowserTest.CallWithSctpDataAndMedia
None of them appear to show up in the current list of flaky tests. 

Expected:
I would expect them to appear in the flaky test list, even with 1 flake. When I checked the list there are 2 tests listed with 1 failure each, so it doesn't appear to ignore tests with a single failure.

[1] https://ci.chromium.org/p/chromium/builders/luci.chromium.try/android-kitkat-arm-rel/82304