[Ada] Tech debt: Remove code duplication

[Ada] Tech debt: Remove code duplication

This patch corrects removes some code duplication within the GNAT
compiler.

gcc/ada/

	* exp_util.adb (Remove_Side_Effects): Combine identical
	branches.
	* sem_attr.adb (Analyze_Attribute): Combine identical cases
	Attribute_Has_Same_Storage and Attribute_Overlaps_Storage.
	* sem_prag.adb (Check_Role): Combine E_Out_Parameter case with
	general case for parameters.
	* sem_util.adb (Accessibility_Level): Combine identical
	branches.
	* sprint.adb (Sprint_Node_Actual): Combine cases for
	N_Real_Range_Specification and N_Signed_Integer_Type_Definition.