compiler: containing small bfunction mixup in Gogo::write_globals

compiler: containing small bfunction mixup in Gogo::write_globals

    Fix buglet in Gogo::write_globals-- in a couple of places the
    wrong Bfunction was being used for the containing (not target)
    function when creating calls for init functions.

    Reviewed-on: https://go-review.googlesource.com/45510

From-SVN: r249159