Previously, spirv-cross would automatically do this (converting to void
function) if shader writes to XFB buffers, however this behavior is
changed in latest spirv-cross version.
So the rasterization disable must be explicitly specified via
spirv-cross’s options now.

Bug: chromium:1159974
Change-Id: I9f34e1cd9d2f1386e8a8d030a800fbd7341eb68f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2596914
Commit-Queue: Le Hoang Quyen <le.hoang.q@gmail.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>