nir/opt_load_store_vectorize: don't vectorize stores across demote

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Fixes: ce9205c03bd ("nir: add a load/store vectorization pass")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7163>
2 files changed