test: remove unnecessary timer

The timer in NAPI's test_callback_scope/test-resolve-async.js
can be removed. If the test fails, it will timeout on its own.
The extra timer increases the chances of the test being
flaky.

PR-URL: https://github.com/nodejs/node/pull/18719
Fixes: https://github.com/nodejs/node/issues/18702


Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>