Unit test on high bit shifts

[ncannasse]

The following tests might give different results depending on platforms:

function shl( x, y ) return x << y;
shl(1,33); // can be 0 or 2, depending if native CPU opcode is used (which does &31 on shift value)

https://c9x.me/x86/html/file_module_x86_id_285.html

I think we should make it platform agnostic, but I'm curious to know if the issue is HL specific or if some other platforms are affected.

[Simn]

This gives me 2 an all targets (that I tested) except Eval.

[ncannasse]

Oh so OCaml is indeed doing something very specific regarding to bit shifting.
This explains why the compiled version of 1 << 33 (using compiler optimisation) differs from 1 << 33 at runtime.
I guess we should add a "land 31" to all bit shifts (both optimizer and eval) to match other targets.

[Simn]

This also fails on PHP and python.