add Binaryen(Get|Set)AllowHeavyweight to binaryen-c.h

[MaxGraey]

It's finished #3032 and fix AssemblyScript/assemblyscript#1449

[dcodeIO]

Looks good, this will fix the issue encountered on our end. Wondering though if we should add a test calling allowHeavyweight and the other (rather new) optimization options like inlining sizes to test/binaryen.js/kitchen-sink.js to test/binaryen.js/inlining-options.js, to be sure.

[dcodeIO]

Took the liberty to merge this one as it's rather straight forward and only affecting parts of Binaryen that I'm relatively familiar with. Let me know if you'd prefer to be involved in review of trivial fixes like these instead :)

[kripken]

@dcodeIO 👍 I think it's great to review and merge straightforward stuff like this as you did!

And thanks @MaxGraey for the PR!

[MaxGraey]

@kripken Thanks you! Btw I also found sometimes we could got compiler's halt problem when try inline recurcive functions, so I created another PR which fix that: #3085