JS API: importing globals

[vouillon]

I'm wondering whether the 'read the imports' process should be updated. As far as I can see, when importing a global (step 3.5), the imported value should be either a number or should implement Global. So, it currently does not allow to directly import a JavaScript string, for instance.

It seems that, when the global has a reference type, V8 allows to import arbitrary values as long as the type matches. Firefox is currently pickier but allows to import arbitrary values when the global has type externref.

[rossberg]

Good point, I agree it needs some updating to account for reference types. And corresponding tests.

@takikawa, can you look into this?

[rossberg]

Closed via #467.