Fix shadow samplers with textureProj and vertex shaders. Fixes: dEQP-GLES3.functional.shaders.texture_functions.textureproj.sampler2dshadow_fragment dEQP-GLES3.functional.shaders.texture_functions.textureproj.sampler2dshadow_bias_fragment dEQP-GLES3.functional.shaders.texture_functions.textureprojoffset.sampler2dshadow_fragment dEQP-GLES3.functional.shaders.texture_functions.textureprojoffset.sampler2dshadow_bias_fragment and some of: dEQP-GLES3.functional.shaders.texture_functions.texture*.sampler2dshadow_vertex BUG=angle:925 Change-Id: I080e379ded95469f0486ae9c8bb1756842118a2d Reviewed-on: https://chromium-review.googlesource.com/251530 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Nicolas Capens <capn@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>