This removes yet another list of all our repos.
(Goal is to simplify https://github.com/golang/go/wiki/CreatingSubRepository)
Most of the work was in earlier CL 208697.
Updates golang/go#36047
Change-Id: I9147b959fe6574e2f809091d08d360051b69402e
Reviewed-on: https://go-review.googlesource.com/c/build/+/210461
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>
Brad Fitzpatrick