i965: Reemit vertex state between indirect multi draws

i965: Reemit vertex state between indirect multi draws

If we're doing an indirect draw, prims[i].basevertex is always 0 and the
real base vertex value is in the indirect parameter buffer. We try to
avoid flagging BRW_NEW_VERTICES if prims[i].basevertex doesn't change,
which then breaks down for indirect draws. Thus, if a program uses base
vertex or base instance, and the draw call is indirect, always flag
BRW_NEW_VERTICES.  A new piglit test,
spec/ARB_shader_draw_parameters/drawid-indirect-vertexid tests this.

Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>