Do not crash when referencing a template that does not exist

Before JSF2 migration, we had custom code making sure that page will not crash when including a facelet resource that's not there (instead, a red error message is displayed in the UI).

Avoid this crash is important when dealing with hot reload issues.

For now the corresponding code has not been migrated to JSF2 => let's disable corresponding tests for now.

+ check if this could allow us to remove the custom JSFConfigureListener used for facelet refresh enablement when Nuxeo global dev mode is set.