Add the following tests to show ANGLE's poor behavior with
glWaitSync/glFlush leading to a vkQueueSubmit each time:

FenceSyncTest::MultipleFenceDraw
MultithreadingTestES3::MultithreadFenceDraw
MultithreadingTestES3::MultithreadFenceTexImage

Bug: angleproject:5306
Test: FenceSyncTest::MultipleFenceDraw
Test: MultithreadingTestES3::MultithreadFenceDraw
Test: MultithreadingTestES3, MultithreadFenceTexImage
Change-Id: I16f653af028677e3c621c3b9a7fd5963fa03d656
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2519092Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Tim Van Patten <timvp@google.com>