The trigger for this commit was when we found that we were not calling
nir_metadata_preserve when lowering the layout code. But then I found
that it would be better to just update the code to use
nir_shader_instructions_pass, so we can avoid to manually:
* Initialize the nir_builder
* Call nir_foreach functions (we pass the callback)
* Call nir_metadata_preserve functions (that as mentioned we were not calling)
We also get a nice cleanup of several functions by reducing the number
of parameters (we pass a state struct).
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17609>
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