intel/brw: Use fs_visitor instead of backend_shader in various passes

And since we are touching them, rename a couple of passes
to follow same name convention as existing ones.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27861>

src/intel/compiler/brw_ir_performance.cpp

@@ -1013,7 +1013,7 @@ namespace {
     * Estimate the performance of the specified shader.
     */
    void
-   calculate_performance(performance &p, const backend_shader *s,
+   calculate_performance(performance &p, const fs_visitor *s,
                          void (*issue_instruction)(
                             state &, const struct brw_isa_info *,
                             const backend_instruction *),