Vulkan: Unskip tests with passthrough GLSL function
Vulkan: Unskip tests with passthrough GLSL function

The 2 end2end tests added by a62ee4d1 no longer fail with latest
Pixel ICDs. Enable those tests as regression checks.

Tests: angle_end2end_tests --gtest_filter=*SamplerPassthrough*Vulkan*
Bug: angleproject:5457
Change-Id: I53fb06fffa3fc76ef6f9a9e811ef5b833577ed67
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2595389
Reviewed-by: Cody Northrop <94770d7fe1cce6ea0791fa9927c1107de4d2e37b@google.com>
Commit-Queue: Mohan Maiya <fbcab303f71178634c736986d06722fc897795f2@samsung.com>

ppy/angle,ppy/angle,ppy/angle,ppy/angle