Test whether llvm and Cranelift allow usize::MAX array lengths

[rtfeldman]

According to rust-lang/rust#67186 LLVM only permits generating arrays (or perhaps indexing into them) of isize::MAX as opposed to the theoretical maximum of usize::MAX imposed by the size of a pointer. (Apparently the reason for the restriction is related to doing pointer arithmetic potentially involving negative numbers, which a language like C would permit in userspace.)

Is this still true? Inkwell's API doesn't suggest or mention it, so it seems worth verifying empirically. What about for Cranelift? (If it's not true, it seems better to go with usize::MAX since Roc doesn't support arbitrary pointer arithmetic.) Probably the easiest way to verify it is through a List.range test.

If it is true, how should we enforce this? Error if attempting to create a list that's over isize::MAX elements?

[rtfeldman]

Error if attempting to create a list that's over isize::MAX elements?

Yes! Closing in favor of #3299