test: add bug436, valid code that crashed gccgo
test: add bug436, valid code that crashed gccgo

R=golang-dev, bsiegert, rsc
CC=golang-dev
http://codereview.appspot.com/6158046
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go