[1/2] Implement the fs.File.read operation

[oleiade]

What?

This Pull Request adds an read method to the k6/experimental/fs module's file object, as per #3145.
⚠️ This PR is based on the experimental/fs branch ⚠️

It allows to read a file into an ArrayBuffer.

The method resolves to either the number of bytes read during the operation or EOF (null) if there was nothing more to read.

It is possible for a read to successfully return with 0 bytes. This does not indicate EOF.

const f = fs.openSync('myfile.txt')

export default function () {
    const buf = new Uint8Array(100);
    const numberOfBytesRead = await file.read(buf); // 11 bytes
}

Checklist

• I have performed a self-review of my code.
• I have added tests for my changes.
• I have run linter locally (make ci-like-lint) and all checks pass.
• I have run tests locally (make tests) and all tests pass.
• I have commented on my code, particularly in hard-to-understand areas.

Related PR(s)/Issue(s)

ref #3165
closes #3145

[codecov-commenter]

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