This updates the packages from text and net to use
the Unicode 11 tables.

Updates golang/go#27945

Change-Id: I096e80283f37b596f2aa8bd3e5ffec6b7045469a
Reviewed-on: https://go-review.googlesource.com/c/go/+/174057
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>