test: harden tmpdir/rmdirSync error handling

This makes rmdirSync call itself after handling ENOTEMPTY, EEXIST, EPERM
errors instead of directly using fs.rmdirSync to handle the possibility
of such errors repeating on the next try (i.e. FS finished writing new
file just as we are done with our loop to delete all files).

Refs: nodejs#29852

test/common/tmpdir.js

@@ -83,7 +83,7 @@ function rmdirSync(p, originalEr) {
           rimrafSync(path.join(p, f));
         }
       });
-      fs.rmdirSync(p);
+      rmdirSync(p, null);
       return;
     }
     throw e;