Access to undefined constants will now always result in an Error
exception being thrown.
This required quite a few test changes, because there were many
buggy tests that unintentionally used bareword fallback in combination
with error suppression.
This only involves switching zval_dtor to zval_ptr_dtor for arrays
and making the convert_to_object for arrays a bit more generic.
All the other changes outside zend_operators.c just make use of
this new ability (use COPY instead of DUP).
What's still missing: Proper references handling. I've seen many
convert_to* calls that will break when a reference is used.
Also fixes bug #69788.
