Breaks when importing a module that uses ESM

In Meteor 2.3+, importing a module that uses [esm](https://github.com/standard-things/esm) causes the server to crash with a `module.export is not a function` error.

I have made a minimal reproducible example [here](https://github.com/TaylorBeeston/Reify-ESM-Bug).

In that repo, I have tested and verified that Meteor 2.2.4 (the last release before Node 14) works, and 2.3 and above crash with that error.

Interestingly, this error only happens if you import an ESM package in server-side code, _not_ on client-side code.

I imagine this issue was created by Node 14 natively supporting ESModules, but I don't have a deep enough understanding of Meteor/Reify to be able to offer any kind of fix =/