go/internal/gccgoimporter: support embedded field in pointer loop

go/internal/gccgoimporter: support embedded field in pointer loop

    Backport of https://golang.org/cl/194440.  Original description:

        If an embedded field refers to a type via a pointer, the parser needs
        to know the name of the embedded field. It is possible that the
        pointer type is not yet resolved. This CL fixes the parser to handle
        that case by setting the pointer element type to the unresolved named
        type while the pointer is being resolved.

    Updates golang/go#34182

    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/194562

From-SVN: r275606