i8Portable is not handle all cases and overcomplicated

[MaxGraey]

I suggest replace i8Portable implementation which currently looks like this:

function checkBitOnByte(bitPosition, byte) {
  return (byte & (1 << bitPosition)) != 0;
}

function i8Portable(param) {
  // JS ints are all i32, therefore, get the sign bit, and then convert accordingly
  // Example: https://blog.michaelyin.info/convert-8bit-byte-to-signed-int/
  let response = param;
  if (checkBitOnByte(7, response)) {
    response = (256 - param) * -1;
  }

  return response;
}

And not handle this case for example:

i8Portable(260) // return 260 but should 4

To this:

function i8Portable(param) {
  return param << 24 >> 24;
}