test: add test case miscompiled by gccgo
test: add test case miscompiled by gccgo

R=golang-dev, bradfitz, rsc, iant
CC=golang-dev
https://codereview.appspot.com/7240043

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