opts is not an object

[lastmjs]

Here opts is assumed to be an object, but in one of our code paths it was a string like utf-8: https://github.com/second-state/wasmedge-quickjs/blob/main/modules/internal/fs/stream.js#L202

I've added this code to fix it temporarily: opts = typeof opts !== 'object' ? {} : opts;

[L-jasmine]

I'm not very familiar with JavaScript, so if there are bugs like this in JavaScript, feel free to submit a pull request to help us optimize it.