ada: Clean up handling of inlining of finalizer procedures

ada: Clean up handling of inlining of finalizer procedures

Change Is_Finalizer from synthesized attribute into flag. Remove duplicate
Is_Finalizer_Proc. Add new Try_Inline_Always for backend usage.

gcc/ada/

	* einfo-utils.ads (Is_Finalizer): Delete.
	* einfo-utils.adb (Is_Finalizer): Delete.
	* einfo.ads: Adjust comment.
	* gen_il-fields.ads, gen_il-gen-gen_entities.adb: Add Is_Finalizer
	flag.
	* exp_ch3.adb (Build_Init_Procedure): Set it.
	* exp_ch7.adb (Create_Finalizer): Likewise.
	* exp_util.adb (Try_Inline_Always): New function.
	* exp_util.ads (Try_Inline_Always): New function.
	* sem_elab.adb (Is_Finalizer_Proc): Replace with Is_Finalizer.