The vertex processor doesn't need to know.

V3: also remove from GL side, which didn't use it either.

Change-Id: Id0624fb2700222be6238a8449b32b334755a45e7
Reviewed-on: https://swiftshader-review.googlesource.com/c/25332Tested-by: Chris Forbes <chrisforbes@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>