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: I93ffb6c6dd38f26e2156a374b1b58ecc3a5f250b
Reviewed-on: https://chromium-review.googlesource.com/301450Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Cooper Partin <coopp@microsoft.com>