String-case in template_from_string
String-case in template_from_string

Fixes #1829 caused by https://github.com/twigphp/Twig/pull/1807/files#diff-5e190f538c5c328c7473a5cfd3b7cd95R578

As twig allows many types in twig templates, e.g. array or traversable, we can do the same for string.
But we only take this approach for twig exposed function/filters etc, i.e. template code, but not core code.
framewr/Twig,moufmouf/Twig,twigphp/Twig,loi-chuanoi/Twig,iKwinto/Twig,hhamon/Twig,nicolas-grekas/Twig,craue/Twig,fsw/Twig,huang53798584/Twig,fsw/Twig,iKwinto/Twig,nicolas-grekas/Twig,derickr/Twig,twigphp/Twig,fsw/Twig,Rvanlaak/Twig,jamessingizi/Twig,jamessingizi/Twig,moufmouf/Twig,gamernetwork/Twig,znerol/Twig,dkarvounaris/Twig,gencer/Twig,derickr/Twig,dkarvounaris/Twig,dkarvounaris/Twig,Rvanlaak/Twig,jamessingizi/Twig,gamernetwork/Twig,znerol/Twig,derickr/Twig,craue/Twig,gencer/Twig,twigphp/Twig,apishka/templater,Rvanlaak/Twig,nicolas-grekas/Twig,framewr/Twig,hhamon/Twig,gamernetwork/Twig,framewr/Twig,znerol/Twig,iKwinto/Twig,nicolas-grekas/Twig,moufmouf/Twig,huang53798584/Twig,huang53798584/Twig,nicolas-grekas/Twig,hhamon/Twig,apishka/templater