i965: Include VUE handles for GS with invocations > 1.

i965: Include VUE handles for GS with invocations > 1.

We always resort to the pull model for instanced GS inputs.  So, we'd
better include the VUE handles, or else we can't actually pull anything.

Ian reports that on his branch with OES_geometry_shader enabled,
this fixes a bunch of dEQP-GLES31.functional.geometry_shading tests::

- instanced.draw_2_instances_geometry_2_invocations
- instanced.draw_2_instances_geometry_8_invocations
- instanced.draw_4_instances_geometry_2_invocations
- instanced.draw_4_instances_geometry_8_invocations
- instanced.draw_8_instances_geometry_2_invocations
- instanced.draw_8_instances_geometry_8_invocations
- instanced.geometry_2_invocations
- instanced.geometry_32_invocations
- instanced.geometry_8_invocations
- instanced.geometry_max_invocations
- instanced.geometry_output_different_2_invocations
- instanced.geometry_output_different_32_invocations
- instanced.geometry_output_different_8_invocations
- instanced.geometry_output_different_max_invocations
- instanced.invocation_output_vary_by_attribute
- instanced.invocation_output_vary_by_texture
- instanced.invocation_output_vary_by_uniform
- query.primitives_generated_instanced

Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Tested-by: Ian Romanick <ian.d.romanick@intel.com>