Move both SemaphoreTests to crashing.
Don't skip passing VulkanExternalImageTest.*.
Explicitly list VulkanExternalImageTest.* tests that still crash.

All these tests compile now.

Bug: angleproject:5721
Change-Id: Ib529dff8895496925001e4649aabcae78ce77236
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2739725
Commit-Queue: Lubosz Sarnecki <lubosz.sarnecki@collabora.com>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>