fn getrandom<'tcx>(
    this: &mut MiriInterpCx<'_, 'tcx>,
    ptr: &OpTy<'tcx, Provenance>,
    len: &OpTy<'tcx, Provenance>,
    flags: &OpTy<'tcx, Provenance>,
    dest: &PlaceTy<'tcx, Provenance>
) -> InterpResult<'tcx>