glsl: Drop borrow/carry lowerings in favor of nir

glsl: Drop borrow/carry lowerings in favor of nir

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>