doc/code: update newmath.Sqrt test case to make sure test succeed         Fixes issue 3445.
doc/code: update newmath.Sqrt test case to make sure test succeed
        Fixes issue 3445.

R=golang-dev, rsc, mtj
CC=golang-dev
http://codereview.appspot.com/5975061

dsriram/golang,dsriram/golang,dsriram/golang,gnanderson/go,apparentlymart/golang,apparentlymart/golang,tv42/old-go,pombredanne/go-deleteme,gnanderson/go,pombredanne/go-deleteme,apparentlymart/golang,apparentlymart/golang,tv42/old-go,gnanderson/go,dsriram/golang,pombredanne/go-deleteme,tv42/old-go,apparentlymart/golang,gnanderson/go,apparentlymart/golang,pombredanne/go-deleteme,apparentlymart/golang,tv42/old-go,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,pombredanne/go-deleteme,dsriram/golang,gnanderson/go,gnanderson/go,gnanderson/go,tv42/old-go,dsriram/golang,dsriram/golang