[GR-62667] Implement Deferring Module Evaluation Proposal

[woess]

TL;DR

We plan to implement Deferring Module Evaluation in GraalJS.

Details

The proposal is to have a new syntactical import form which will only ever return a namespace exotic object. When used, the module and its dependencies would not be executed, but would be fully loaded to the point of being execution-ready before the module graph is considered loaded.

Only when accessing a property of this module, would the execution operations be performed (if needed).

This way, the module namespace exotic object acts like a proxy to the evaluation of the module, effectively with [[Get]] behavior that triggers synchronous evaluation before returning the defined bindings.

The API will use the below syntax:

import defer * as yNamespace from "y";