Function translate_child_block

fn translate_child_block(
    info: &mut BlockInfo<'_>,
    parent_loops: &Vec<BlockId>,
    switch_exit_blocks: &HashSet<BlockId>,
    parent_span: Span,
    child_id: BlockId,
) -> Option<Block>

parent_span: we need some span data for the new statement. We use the one for the parent terminator.