nir/lower_tex: handle lower_tg4_offsets with lower_tg4_broadcom_swizzle

nir/lower_tex: handle lower_tg4_offsets with lower_tg4_broadcom_swizzle

This pass uses a safe iterator so it can't lower new instructions that are
injected as part of the lowering, which is exactly what lower_tg4_offsets
does, and if lower_tg4_broadcom_swizzle is also set then we need to lower
these new instructions. Handle this by running the pass twice when both
are set: the first pass will only handle lower_tg4_offsets and
the second pass (which will see the new tg4 instructions produced with
lower_tg4_offsets) will process the remaining options, including
lower_tg4_broadcom_swizzle.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23616>