test: make sure test function resolves in test-worker-debug

Use the common `.then(common.mustCall())` check to verify that.
Also, we should not use `process.abort()` in `test/parallel`; if
the test fails, that leaves core dumps lying around on POSIX systems.

PR-URL: https://github.com/nodejs/node/pull/28155


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>