test(ses): Coverage for module source validation

[kriskowal]

Description

This change increases coverage and consistency of error messages for invalid module sources.

Security Considerations

None.

Scaling Considerations

None.

Documentation Considerations

None.

Testing Considerations

It’s tests all the way down.

Compatibility Considerations

There is a possibility that this will break tests that are over-constrained on error messages.

Upgrade Considerations

None.

[erights]

@kriskowal , is this still relevant?

[kriskowal]

@kriskowal , is this still relevant?

Yes, this is still desirable and will inform tests for hardened262