Check that block instance name isn't reserved BUG=angleproject:1060 TEST=dEQP-GLES3.functional.shaders.uniform_block.invalid.* Change-Id: I6de3aa0f714d585e7821798744530f3e51ddee7f Reviewed-on: https://chromium-review.googlesource.com/284259 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Zhenyao Mo <zmo@chromium.org> Tested-by: Olli Etuaho <oetuaho@nvidia.com>