glsl: Allow gl_InvocationID and gl_Layer with GL_OES_geometry_shader

glsl: Allow gl_InvocationID and gl_Layer with GL_OES_geometry_shader

Fixes

dEQP-GLES31.functional.geometry_shading.layered.fragment_layer_2d_array
dEQP-GLES31.functional.geometry_shading.layered.fragment_layer_2d_multisample_array
dEQP-GLES31.functional.geometry_shading.layered.fragment_layer_3d
dEQP-GLES31.functional.geometry_shading.layered.fragment_layer_cubemap

v2: Don't enable gl_ViewportIndex in GLSL ES 3.20.  Noticed by Ilia.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>