Vulkan: Suppress ClearIssue test. This test was flaky, the failure was missed on the CQ. Bug: angleproject:2484 Change-Id: Ic3c32bcd385620683e9a01acf37d62bbf3ca8797 Reviewed-on: https://chromium-review.googlesource.com/1014733 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>