Revert "Mark handlebars test as failing"

This reverts commit 70e35dd8c715b3343d922ed3b51c8de0aa4c8e82.

The problem was fixied with handlebars.js 2.0.0-alpha.1, see
https://github.com/wycats/handlebars.js/issues/727
https://github.com/wycats/handlebars.js/releases/tag/vv2.0.0-alpha.1