Added the alphaToCoverage functionality with some
end2end tests. There is no validation for disabling alphaToCoverage
mode if SV_Coverage is statically used by the shader yet.
Bug: dawn:494
Change-Id: I9df15b35697ea05a064b092edae9d5d20f73c4d8
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/25761
Commit-Queue: Tomek Ponitka <tommek@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>