[WIP] Fix byteLength of subarray

[LinusU]

It seems like the end argument was treated as the length in the subarray function.

This was part of the test before:

arr = arr.subarray(1, 2);
assert(arr.length == 1);
assert(arr.byteOffset == 1 * sizeof<i32>());
assert(arr.byteLength == 2 * sizeof<i32>());

But the byteLength should be equal to arr.length * sizeof<i32>(), right?

The tests are still failing though so need to investigate more when I have time, opening for visibility...

[MaxGraey]

Thank you for paying attention to this. This has been fixed in #328