Update visibility checks in Vulkan to support geom shaders

Bug: skia:
Change-Id: Ie80bea38e644647e5a09e95053ddace30521361d
Reviewed-on: https://skia-review.googlesource.com/23300
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
2 files changed