Only use gl_PointSize if GL_PROGRAM_POINT_SIZE is enabled
Fixes:
GTF-GL33.gtf32.GL3Tests.draw_elements_base_vertex.draw_elements_base_vertex_mode
GTF-GL33.gtf32.GL3Tests.draw_elements_base_vertex.draw_elements_base_vertex_count
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
Fixes:
GTF-GL33.gtf32.GL3Tests.draw_elements_base_vertex.draw_elements_base_vertex_mode
GTF-GL33.gtf32.GL3Tests.draw_elements_base_vertex.draw_elements_base_vertex_count