Better global support

[amasad]

In the current implementation, instanceof fails because we get classes like Array and Object from a different realm.

With this, we only copy things that are missing from the context (and the console).

This is implementing https://github.com/replit/goval/pull/1419

[replbot]

Good work, this PRs short and easy to review! Promoting to bop.

[replbot]

unbooping: changes requested. Make sure to address everyone's comments and dismiss any reviews before booping.

[amasad]

• Removed globals
• Added more tests
• Fixed nits