Ada: Fix bogus error on aggregate in call with qualified type in instance

Ada: Fix bogus error on aggregate in call with qualified type in instance

This happens with a container aggregate in the testcase, although this can
very likely happen with a record aggregate as well.  The trick used in the
Save_Global_References procedure for aggregates loses the qualification of
the type of the formal for which the aggregate is the actual.

gcc/ada/
	PR ada/123302
	* sem_ch12.adb (Save_Global_Reference.Save_References_In_Aggregate):
	Recurse on the scope of the type to find one that is visible, in the
	case of an actual in a subprogram call with a local type.

gcc/testsuite/
	* gnat.dg/aggr34.adb: New test.
	* gnat.dg/aggr34_pkg1.ads, gnat.dg/aggr34_pkg1.adb: New helper.
	* gnat.dg/aggr34_pkg2.ads, gnat.dg/aggr34_pkg2.adb: Likewise.
	* gnat.dg/aggr34_pkg3.ads: Likewise.