constexpr.c (cxx_eval_store_expression): Don't set CONSTRUCTOR_NO_IMPLICIT_ZERO if we have an enclosing CONSTRUCTOR...

	* constexpr.c (cxx_eval_store_expression): Don't set
	CONSTRUCTOR_NO_IMPLICIT_ZERO if we have an enclosing CONSTRUCTOR
	without it.
	(cxx_eval_array_reference): Check it.

From-SVN: r226948