Reject template wrappers from another environment

[fabpot]

Twig now rejects TemplateWrapper instances created by another Environment.

This prevents templates from unexpectedly using another environment's loader, extensions, globals, or sandbox policy.

[stof]

This will break the Symfony form renderer, which relies on the internal API: https://github.com/symfony/symfony/blob/f1072d8902e3d397ab5f9190877fb947d259b0c3/src/Symfony/Bridge/Twig/Form/TwigRendererEngine.php#L142

It might make sense to first refactor Symfony to stop using the internal API (which will be safer regarding semver guarantees)