unicode/norm: test unused tables are dropped

Change-Id: Ie068d74c4c66a7bc38945e3c3b092349fad9d26e
Reviewed-on: https://go-review.googlesource.com/36870
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
1 file changed