This reverts CL 207352

Reason for revert: broke more builders than it fixed. 😞

Change-Id: Ic5adefe92edfa2230b9c7d750c922473a6a5ded4
Reviewed-on: https://go-review.googlesource.com/c/go/+/207477Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>