Unconditionally lowering prevents GL drivers from natively implementing these ops. Drivers that need lowering should set lower_uadd_carry and lower_usub_borrow on nir_shader_compiler_options to get the nir lowerings. Tested with dEQP-GLES31.functional.shaders.builtin_functions.integer.* Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com> Reviewed-by: Emma Anholt <emma@anholt.net> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19704>