Vulkan doesn't require any fixed-function vertex and pixel processing.

Bug b/117152542

Change-Id: I4c758c70ff97a785c263c38497e7fb435b81b05d
Reviewed-on: https://swiftshader-review.googlesource.com/c/22148Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>