ada: Fix debug info for aliased packed array with unconstrained nominal subtype

ada: Fix debug info for aliased packed array with unconstrained nominal subtype

The front-end now rewrites it as a renaming when it is initialized with a
function call and the same processing must be applied in the renaming case
as in the regular case for this kind of special objects.

gcc/ada/

	* gcc-interface/decl.cc (gnat_to_gnu_entity) <E_Variable>: Apply the
	specific rewriting done for an aliased object with an unconstrained
	array nominal subtype in the renaming case too.