[Ada] Unnesting: fix a missing activation record

[Ada] Unnesting: fix a missing activation record

2018-12-11  Ed Schonberg  <schonberg@adacore.com>

gcc/ada

	* exp_ch7.adb (Check_Unnesting_In_Declarations): Extend
	subprogram so that it is usable for visible and private
	declarations of a package declaration, not just for declarations
	in the pakage body.
	* exp_ch13.adb (Expand_Freeze_Entity): Handle properly the
	freezing of a finalizer routine generated for a controlled objet
	declaration. Special processing already applies to finalizers
	because they are usually displaced into another construct.

From-SVN: r267010