[JS Interop] Scan configureAll in the entire module, not just the start function

[kripken]

Nice finding from fuzzing the start function + PreserveImportsExportsJS: it made
some configureAll function and called it not from the start. We did not handle
that.

Unfortunately we have a const Module which causes a headache in ModuleUtils
here. I added a small workaround for that - but maybe there is a better way?

[kripken]

If we want to avoid this overhead, and it would be nice to, some options:

1. Keep the requirement to do this in the start, and fix the fuzzer instead. But we need to be sure our users aren't doing more.
2. Look for the configureAll once, not a new scan each time we need that info. Perhaps during module load we could convert the configureAll into @binaryen.js.called annotations. Our users should really add those themselves, but this would auto-add it for convenience. With those annotations, we don't need to scan later.

[tlively]

2. Look for the configureAll once, not a new scan each time we need that info. Perhaps during module load we could convert the configureAll into @binaryen.js.called annotations. Our users should really add those themselves, but this would auto-add it for convenience. With those annotations, we don't need to scan later.

Doing this as an opt-in pass but requiring manual annotations by default might be a good compromise. Still maybe surprising for users who expect us to handle configureAll correctly by default, though :/ However, requiring manual annotations is the only solution that is robust for arbitrary usage of configureAll because figuring out what functions are passed to it is undecidable in general.

[kripken]

Good idea, let's do that: #8733