It was removed in CL 27325.

Fixes #20431

Change-Id: I6842851444186e19029d040f61fdf4f87a3103a6
Reviewed-on: https://go-review.googlesource.com/43771Reviewed-by: Ian Lance Taylor <iant@golang.org>
(cherry picked from commit deebd8fe273df2de2d590ee41ae1155c521219e9)
Reviewed-on: https://go-review.googlesource.com/43772Reviewed-by: Chris Broadfoot <cbro@golang.org>