Capture/Replay: Mark test to be flaky on Windows The test is passing quite often, but not always. Bug: angleproject:6180 Change-Id: I4bed6cd2907da61023ca91b20e20d8b0722302b7 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3257321 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>