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.c

@@ -1708,7 +1708,7 @@ nir_index_ssa_defs(nir_function_impl *impl)
    unsigned index = 0;
 
    nir_foreach_block(block, impl) {
-      nir_foreach_instr(block, instr)
+      nir_foreach_instr(instr, block)
          nir_foreach_ssa_def(instr, index_ssa_def_cb, &index);
    }
 
@@ -1725,7 +1725,7 @@ nir_index_instrs(nir_function_impl *impl)
    unsigned index = 0;
 
    nir_foreach_block(block, impl) {
-      nir_foreach_instr(block, instr)
+      nir_foreach_instr(instr, block)
          instr->index = index++;
    }