mesa: add ARB_conditional_render_inverted flags
Also add an extension bit so we can safely enable Reviewed-by:Ilia Mirkin <imirkin@alum.mit.edu> Reviewed-by:
Roland Scheidegger <sroland@vmware.com> Reviewed-by:
Chris Forbes <chrisf@ijw.co.nz> Signed-off-by:
Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>