test: mark test-worker-prof flaky on arm

Refs: https://github.com/nodejs/node/issues/26401#issuecomment-613095719

PR-URL: https://github.com/nodejs/node/pull/32826


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>