[WHLSL] Implement uint/int div safety and add tests

[Saam Barati]

e.g
```
    program = "uint foo(uint x, uint y) { return x / y; }";
    assert_equals(await callUintFunction(program, "foo", [makeUint(7), makeUint(2)]), 3);
```

[Saam Barati]

and

```
    program = "int foo(int x, int y) { return x / y; }";
    assert_equals(await callIntFunction(program, "foo", [makeInt(7), makeInt(2)]), 3);
```

[Saam Barati]

I shall do this

[Saam Barati]

This seems to work now. I'll land tests.

[Saam Barati]

(In reply to Saam Barati from comment #3)
> This seems to work now. I'll land tests.

Though maybe we need to do things to make the div safe

[Saam Barati]

Created attachment 374551 [details]
WIP

[Myles C. Maxfield]

WHLSL is no longer relevant.