cmd/guru: disable a failing test for now

Updates golang/go#19464

Change-Id: I60a77bc25aa8d92c4f2fc1835d96002ea5b8bfea
Reviewed-on: https://go-review.googlesource.com/40850
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Kevin Burke <kev@inburke.com>
1 file changed