module: do not use process.exit()

module: silence ModuleJob unhandled rejection warnings

This could otherwise print unhandled rejection warnings if the process does not exit immediately inside an earlier .catch() handler.

module: do not use process.exit()

Inside workers, using stdio is always asynchronous, so using process.exit() always interrupts sending of messages to the parent thread, including error messages presented over stdio.

Do not use process.exit() and instead use the cleaner process.exitCode directly trigger a “real” uncaught exception.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines