Enable point sprites in StateManagerGL. Test it against multiple versions of the OpenGL renderer so make sure that both core and compatibility profile are tested. Fixes: * conformance/rendering/point-size.html * conformance/rendering/point-with-gl-pointcoord-in-fragment-shader.html * PointSpritesTest * particle_system sample BUG=angleproject:883 Change-Id: Ib7625cb12faeac21016a9ff551aa650ba24e789f Reviewed-on: https://chromium-review.googlesource.com/277692 Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>