Convert bake tests to compare to files

This results in much more comprehensible tests.

It's easy to cheat and [populate the bake compare folder](https://github.com/AD7six/cakephp/commit/475d82846e6e9267470b03bf013e6fea048c6590) should the bake templates be significantly modified in the future.
The keys shouldn't be there. I can fix that issue after this merges.