The test is marked flaky on ARM because it times out on Raspberry Pi
devices in CI. Split the single test file into four separate test files
to ease debugging. Add fs.close() to avoid timing out.
Fixes: https://github.com/nodejs/node/issues/33796
PR-URL: https://github.com/nodejs/node/pull/34203
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Robert Nagy <ronagy@icloud.com>
