[Nouveau] nv50 piglit change between 7.8 and master

[Xavier Chantry]

7.8 branch (533b7663) : 209/246
master branch (c882c31) : 216/241

In short :
8 fail/warn -> pass
5 fail -> skip
1 pass -> fail

So the only regression is glean/clipFlat
Output:
----------------------------------------------------------------------
Test clipping with flat shading (provoking vertex).

clipFlat: Failure for glBegin/End(GL_QUADS), glFrontFace(GL_CCW)
	GL_EXT_provoking_vertex test: GL_FIRST_VERTEX_CONVENTION_EXT mode
	Expected color (0, 1, 0) but found (1, 0, 0)
clipFlat:  FAIL rgba8, db, z24, s8, win+pmap, id 33

If anyone cares, I can host the detailed html results somewhere.