test: fix recursive rm test to actually use tmpdir

Previously folders were created in the root of the project and would
therefore stay there in case of errors. This changes the test to create
all directories in the temp directory (`tmpdir.path`).

PR-URL: https://github.com/nodejs/node/pull/31250


Reviewed-By: Bryan English <bryan@bryanenglish.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>