A particular test waits on a fence that was created in another Context.
Then it immediately destroys all other resources. This triggered a bug
where the VkEvent corresponding to the FenceSync was deleted while it
was still in use by a command buffer. Fix this by referencing the other
submit fence of the second ContextVk in the FenceSync class.
Bug: angleproject:2464
Change-Id: I4ef096bf760aa8943db08d491006c68e36db993b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1757505Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
