nir: Switch the arguments to nir_foreach_instr

This matches the "foreach x in container" pattern found in many other
programming languages.  Generated by the following regular expression:

s/nir_foreach_instr(\([^,]*\),\s*\([^,]*\))/nir_foreach_instr(\2, \1)/

and similar expressions for nir_foreach_instr_safe etc.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/compiler/nir/nir_opt_constant_folding.c

@@ -177,7 +177,7 @@ constant_fold_block(nir_block *block, void *mem_ctx)
 {
    bool progress = false;
 
-   nir_foreach_instr_safe(block, instr) {
+   nir_foreach_instr_safe(instr, block) {
       switch (instr->type) {
       case nir_instr_type_alu:
          progress |= constant_fold_alu_instr(nir_instr_as_alu(instr), mem_ctx);