[Ada] Multidimensional arrays with Iterated_Component_Associations

[Ada] Multidimensional arrays with Iterated_Component_Associations

gcc/ada/

	* sem_aggr.adb (Resolve_Iterated_Component_Association): new
	internal subprogram Remove_References, to reset semantic
	information on each reference to the index variable of the
	association, so that Collect_Aggregate_Bounds can work properly
	on multidimensional arrays with nested associations, and
	subsequent expansion into loops can verify that dimensions of
	each subaggregate are compatible.