nir: store the results of divergence analysis on loops

Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7726>

src/compiler/nir/nir_divergence_analysis.c

@@ -890,6 +890,8 @@ visit_loop(nir_loop *loop, struct divergence_state *state)
                                       loop_state.divergent_loop_break);
    }
 
+   loop->divergent = (loop_state.divergent_loop_break || loop_state.divergent_loop_continue);
+
    return progress;
 }