clover/nir: Register callback for translation messages (v2)

clover/nir: Register callback for translation messages (v2)

This allows us to add SPIR-V to NIR translation failure messages to the
program’s compilation log, which can then be queried by the user.

v2: Replace the if-statement in `debug_function()` with an assert.

Signed-off-by: Pierre Moreau <dev@pmoreau.org>
Reviewed-by: Serge Martin <edb@sigluy.net>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5038>