Description:
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zval_update_constant_ex() evaluates a constant within the scope a class when executed within a class scope.  The new code to support ASTs does not pass this context into the AST evaluator so the class context is lost and references to self::SOME_CONSTANT and parent::SOME_CONSTANT error. 

Test script:
---------------
--TEST--
Terry_002   Problems in AST evaluation invalidating valid parent:: reference
--INI--
opcache.enable=0
opcache.enable_cli=0
opcache.optimization_level=0
--SKIPIF--
--FILE--
<?php
class A { const HW = "this is A"; }
class B extends A { const BHW = parent::HW . " extended by B"; }
const C = B::BHW; 
echo C, "\n";
--CLEAN--	
--EXPECT--
this is A extended by B