We never used it, might as well get rid of it.

Change-Id: I5c23c93e90173bff9ac1fc1b8ae1e2025215d6eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/191938
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>