Implement the File API's File.read method

[oleiade]

As part of #3141, implementing the agreed-upon design for k6's File API, we intend to implement a File.read method.

The read method reads the file into an ArrayBuffer, and resolves to either the number of bytes read during the operation or null (EOF) if there is nothing more to read. Note that it should be possible for a read to be successful and return 0 bytes read while not indicating an EOF.

prototype

interface File {
    read(p ArrayBuffer | TypedArray | DataView): Promise<number>
}

example

const file = fs.openSync("fou.txt")
const buf = new Uint8Array(100);
const numberOfBytesRead = file.readSync(buf)

[oleiade]

Implemented by #3309