It was apparently waiting on CL 36942, which was submitted.

Fixes #21416

Change-Id: I8f4ccc5a3176070abf0df019c82700c5761b5f53
Reviewed-on: https://go-review.googlesource.com/117055
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>