process: make internal/queue_microtask.js more self-contained

[joyeecheung]

• Instead of passing triggerFatalException through node.js,
  simply put it on internalBinding('util') which has to be
  loaded anyway.
• Expose the implementation of queueMicrotask directly instead
  of through an unnecessary factory function.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines