test: remove workaround code in debugger test

Remove code that made a check more lenient to account for a known issue
that is no longer reproducible.

Refs: https://github.com/nodejs/node-inspect/issues/35

PR-URL: https://github.com/nodejs/node/pull/39238


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jan Krems <jan.krems@gmail.com>