Go indexer: Skip Go 1.9 style type aliases.
Go indexer: Skip Go 1.9 style type aliases.

Summary:
This change does not include tests because we can't build them for comparision
until we're actually using the Go 1.9 toolchain (which is not yet released).
I'll add them when we can.

Reviewers: #core_team, zarko, schroederc

Reviewed By: #core_team, zarko, schroederc

Subscribers: #core_team

Differential Revision: https://phabricator-dot-kythe-repo.appspot.com/D1375

legrosbuffle/kythe,legrosbuffle/kythe,bzz/kythe,legrosbuffle/kythe,kythe/kythe,benjyw/kythe,kythe/kythe,kythe/kythe,benjyw/kythe,kythe/kythe,bzz/kythe,benjyw/kythe,benjyw/kythe,bzz/kythe,kythe/kythe,bzz/kythe,kythe/kythe,kythe/kythe,benjyw/kythe,legrosbuffle/kythe,bzz/kythe,bzz/kythe,kythe/kythe,bzz/kythe,legrosbuffle/kythe,benjyw/kythe,benjyw/kythe,benjyw/kythe,legrosbuffle/kythe,bzz/kythe,kythe/kythe,benjyw/kythe,benjyw/kythe,bzz/kythe,bzz/kythe,legrosbuffle/kythe,benjyw/kythe,legrosbuffle/kythe,legrosbuffle/kythe,benjyw/kythe,legrosbuffle/kythe,bzz/kythe,kythe/kythe,legrosbuffle/kythe,bzz/kythe,kythe/kythe