all: update go.mod

The latest x/tools includes the fix
https://go-review.googlesource.com/c/tools/+/192330 for
golang/go#33937.

Updates golang/go#33937

Change-Id: I4af068315fb16aa3d526214f89e4005d792d0c49
Reviewed-on: https://go-review.googlesource.com/c/mobile/+/194497
Run-TryBot: Hajime Hoshi <hajimehoshi@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/go.mod b/go.mod
index fc62116..13a3b3b 100644
--- a/go.mod
+++ b/go.mod
@@ -5,5 +5,5 @@
 require (
 	golang.org/x/exp v0.0.0-20190731235908-ec7cb31e5a56
 	golang.org/x/image v0.0.0-20190802002840-cff245a6509b
-	golang.org/x/tools v0.0.0-20190816200558-6889da9d5479
+	golang.org/x/tools v0.0.0-20190909214602-067311248421
 )
diff --git a/go.sum b/go.sum
index 6e1919b..664c53c 100644
--- a/go.sum
+++ b/go.sum
@@ -17,6 +17,6 @@
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20190312151545-0bb0c0a6e846/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
-golang.org/x/tools v0.0.0-20190816200558-6889da9d5479 h1:lfN2PY/jymfnxkNHlbBF5DwPsUvhqUnrdgfK01iH2s0=
-golang.org/x/tools v0.0.0-20190816200558-6889da9d5479/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20190909214602-067311248421 h1:NmmWqJbt02YJHmp4A4gBXvsXXIzzixjzE1y6PKUyIjk=
+golang.org/x/tools v0.0.0-20190909214602-067311248421/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=