Revert "Fix bug #68446 (bug with constant defaults and type hints)"

This reverts commit 5ef138b0c7c4e9532e205f45c18a72aa1d279c24.
Revert NEWS and set test to XFAIL
Merge remote-tracking branch 'origin/PHP-5.6'

Conflicts:
	Zend/zend_compile.c
	Zend/zend_execute.c
	Zend/zend_vm_def.h
	Zend/zend_vm_execute.h