i965: Use the VAOs binding information in array setup.

i965: Use the VAOs binding information in array setup.

The change basically reimplements array setup by walking
the gl_contex::Array._DrawVAO on a per binding sequence.
In this way we can make direct use of the application
provided minimum set of buffer objects and emit fewer relocs.

v2: Rebase onto:
    compiler: Move double_inputs to gl_program::DualSlotInputs
v3: Rebase onto introduction of gl_vertex_format
v4: Reorder and extend patch series.
v5: Split out two hunks into seperate patches.
v6: Avoid using GL* types.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Mathias Fröhlich <Mathias.Froehlich@web.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/308>