fix: Incorrect exports

[timfish]

Closes #68, Closes #77, Closes #62, Closes #60...

We need to mimic the behaviour of Node ESM resolution and my testing so far without the loader suggests that:

• export * from only exports named exports and we don't need to pass through default exports
• If there are duplicate named exports, none of these should be exported

Ideally we should have tests that ensure that module exports are identical both with and without the loader hook because currently this isn't the case.

To accomplish the above:

• I've added mapExcludingDuplicates for setters which does as it suggests
• Removed auto-renaming of default exports as this doesn't appear to be what Node does (ie. renamedExport handling incorrectly adds ES module exports #68)
• Use the export name as the Map key so we remove duplicates
• In the emitted code, only add exports to _ if there a corresponding key in set. Without this, the exports passed to Hook don't match the final module exports

[jsumners-nr]

The intention of this test is to verify that we can load modules like got. Can you clarify the reasoning behind removal of the removed code?

[timfish]

It's adding exports that don't exist when the loader is not in use. When testing Node without the loader, only the root default export is exposed. export * from does not include default exports.

We probably just need to add a load of troublesome libraries to devDependencies and actually test them in the tests rather than rely on synthetic test cases.

[jsumners-nr]

We probably just need to add a load of troublesome libraries to devDependencies and actually test them in the tests rather than rely on synthetic test cases.

Agreed.

[jsumners-nr]

Looks good to me.

[timfish]

Closing in favour of #85 which removes more redundant code