This change fixes a Shader error on FL9_3 that reports
Vertex/Pixel Shader linkage signatures between stages
being incompatible when glPointCoord is used without glPointSize.

Change-Id: I107d06692c5375c07544038f5f4429c1e8d6e313
Reviewed-on: https://chromium-review.googlesource.com/305395Tested-by: Cooper Partin <coopp@microsoft.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>