radeonsi: generate GS prolog to (partially) fix triangle strip adjacency rotation

radeonsi: generate GS prolog to (partially) fix triangle strip adjacency rotation

Fixes GL45-CTS.geometry_shader.adjacency.adjacency_indiced_triangle_strip and
others.

This leaves the case of triangle strips with adjacency and primitive restarts
open. It seems that the only thing that cares about that is a piglit test.
Fixing this efficiently would be really involved, and I don't want to use the
hammer of degrading to software handling of indices because there may well
be software that uses this draw mode (without caring about the precise
rotation of triangles).

v2:
- skip the GS prolog entirely if workaround is not needed
- only check for TES (TES is always non-null when tessellation is used)

Reviewed-by: Marek Olšák <marek.olsak@amd.com>