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

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