This reverts commit 69e46942.
Reason for revert: Broke the build due to VulkanExternalHelper API change
Original change's description:
> Vulkan: Add semaphores test to VulkanExternalImageTest
>
> Add a more substantial test that uses semaphores to
> VulkanExternalImageTest.
>
> It's still just a clear in GL, which exposed a bug that a staged clear
> wasn't be flushed by a call to glSignalSemaphoreEXT.
>
> Bug: angleproject:3289
> Change-Id: Id938eaf2c8c20cb0ae9fb948fbfcf3448980b577
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2195684
> Commit-Queue: Michael Spang <spang@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Geoff Lang <geofflang@chromium.org>
TBR=spang@chromium.org,geofflang@chromium.org,jmadill@chromium.org
Change-Id: I50b2af80cd0214bd3c317eb5ba211ddc66803d74
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: angleproject:3289
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2197193Reviewed-by: Michael Spang <spang@chromium.org>
Commit-Queue: Michael Spang <spang@chromium.org>
