Add ARB_shader_viewport_layer_array support to
SH_SELECT_VIEW_IN_NV_GLSL_VERTEX_SHADER.

Bug: angleproject:3404
Change-Id: Ia89517d0cc92400ce47c9118e8c1abf8285aec41
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1585452Reviewed-by: Jamie Madill <jmadill@chromium.org>