internal/number: enable the fast case more often

Change-Id: I0849b029eee7b233f4c6f676d7bbdde3820c63e4
Reviewed-on: https://go-review.googlesource.com/46470
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