Decompression: Pass uncompressed buffer length to decompression codec

[talawahtech]

Most ZSTD WASM implementations benefit from being given the length of uncompressed buffer. It looks like flechette already has the value. It would be convenient if it were passed along to codec.decode as a parameter.

[jheer]

Sounds good to me. Feel free to make a pull request; otherwise I will try to get to this soon. Thanks!