Use globals npm package to set environments

This is a very simple approach that maintains parity with what was there before. In the future a slightly more programmatic solution could be undertaken to automatically expand the environment sets as they come in from the globals module.

Resolves #1577
sindresorhus/globals#4
I like `globals` having it under `builtin` even if that isn't technically accurate, as it suits the purpose of avoiding clobbering identifiers that have special meaning, but I understand why it's handled differently here. This seemed like an easy enough resolution.