testing: bad anchor text in doc comment

[gopherbot]

by feedback.test.account:

https://feedback.corp.google.com/#/Report/1043866566

Description:
Anchor not exists.

UI language: en
Detected language: en

[adg]

Comment 1:

The link to the Go tool docs from http://golang.org/pkg/testing/ is bad, but is fixed at
tip.

Labels changed: removed restrict-view-owner.

Owner changed to @adg.

Status changed to Fixed.