native runtime: implement memory bounds check

[yamt]

Fixes:
#750
#709

[JerwuQu]

@aduros could you take a look at this?

[aduros]

I like the bounds check here, but do we necessarily need to do an overflow checked multiply? I think we can live with possible overflows, as long as it doesn't allow out of bounds access somehow?

[yamt]

to implement bounds check that way, we need to make this module (runtime.c) know the implementation details of w4_framebufferBlit. or, implement bounds check in w4_framebufferBlit itself.

IMO, it's simpler to perform overflow checks here.

[aduros]

Ah, I see. Passing huge values for width/height here that result in an overflow here would fool the bounds check and result in OOB in w4_framebufferBlit. Nice catch!