cmd/callgraph: exclude test for Android

For golang/go#11811.

Change-Id: I4cec398a0a6d43f3297c205f73193522928a5b31
Reviewed-on: https://go-review.googlesource.com/13280
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
1 file changed