glsl: Allow invocations layout qualifier with GL_OES_geometry_shader

glsl: Allow invocations layout qualifier with GL_OES_geometry_shader

Fixes

dEQP-GLES31.functional.geometry_shading.instanced.geometry_1_invocations
dEQP-GLES31.functional.geometry_shading.instanced.invocation_per_layer_2d_array
dEQP-GLES31.functional.geometry_shading.instanced.invocation_per_layer_2d_multisample_array
dEQP-GLES31.functional.geometry_shading.instanced.invocation_per_layer_3d
dEQP-GLES31.functional.geometry_shading.instanced.invocation_per_layer_cubemap
dEQP-GLES31.functional.geometry_shading.instanced.multiple_layers_per_invocation_2d_array
dEQP-GLES31.functional.geometry_shading.instanced.multiple_layers_per_invocation_2d_multisample_array
dEQP-GLES31.functional.geometry_shading.instanced.multiple_layers_per_invocation_3d
dEQP-GLES31.functional.geometry_shading.instanced.multiple_layers_per_invocation_cubemap
dEQP-GLES31.functional.geometry_shading.query.geometry_shader_invocations

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>