html: fix escape_test.go for CSS escaper change 5306042.
html: fix escape_test.go for CSS escaper change 5306042.

R=mikesamuel
CC=golang-dev
http://codereview.appspot.com/5313044
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go