Make PLS coherent on Vulkan Uses the VK_EXT_fragment_shader_interlock extension to make the shader image implementation of PLS coherent on Vulkan. This extension is supported on AMD, Apple, NVIDIA, and Intel. Bug: angleproject:7279 Change-Id: Ic0253eb20932eb6be0b1f433ba454e48b57be2f5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3813816 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Chris Dalton <chris@rive.app> Reviewed-by: Geoff Lang <geofflang@chromium.org>