Add support for arrays as function return values in GLSL output Output the array brackets and the array size correctly when a function's return value type is array. Tested with WebGL 2 test sdk/tests/deqp/data/gles3/shaders/arrays.html BUG=angleproject:971 TEST=WebGL 2 conformance tests Change-Id: I63aa8c54d2696f65351b23acb0749a487298ddfb Reviewed-on: https://chromium-review.googlesource.com/265410 Tested-by: Olli Etuaho <oetuaho@nvidia.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>