Simplify `!(x <= y)` to `x > y` and `!(x >= y)` to `x < y` where x,y are not defined as float.

Change-Id: Id1e5b518395d97e75f96aa4ac5d6c0ee990c0e7d
Reviewed-on: https://go-review.googlesource.com/c/140337
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>