Use exceptions in the Err case of Number.parseInt

[ospencer]

Right now the errors are just plain strings. It'd be more useful if they were exceptions we could pattern match on.

Blocked on #1053

[phated]

This is unblocked because Result is available as a language-supplied type now.

[spotandjake]

This has been blocked by #1758 or #1759 either one would allow this to move forward.

A decision was made to use enums in the case of exceptions the reason this is blocked is because you cannot re-export the enum to get this working properly.

[spotandjake]

We are going to switch this back to using an enum instead of an exception which means this is blocked on #1886