ada: Fix finalization issue introduced by previous change

When detecting calls to subprograms specified for aspects of a type, the
entity denoted by the aspects must go through Ultimate_Alias, since that
of the name of the calls did the same.

gcc/ada/ChangeLog:

	* exp_ch6.adb (Expand_Call_Helper): Call Ultimate_Alias for the
	detection of calls to subprograms specified for Constant_Indexing.
	* exp_util.adb (Is_Indexed_Container): Likewise.
	(Is_Iterated_Container): Likewise for Default_Iterator.