Feature Request

Is your feature request related to a problem? Please describe.
I would like to use "top-level" await in a babel-node REPL. This is doable in vanilla Node with the --experimental-repl-await command line flag. Attempting to run babel-node with this flag currently results in:

  error: unknown option `--experimental-repl-await'

Describe the solution you'd like
Support the Node --experimental-repl-await flag.

Describe alternatives you've considered
There's a top-level await TC39 proposal in the works, but it's still early (stage 2), with plenty of details to be worked out, and there is no Babel implementation yet (if ever?). The repl flag is already implemented in Node and much more limited in scope.