ada: No need to follow New_Occurrence_Of with Set_Etype

ada: No need to follow New_Occurrence_Of with Set_Etype

Routine New_Occurrence_Of itself sets the Etype of its result; there is
no need to set it explicitly afterwards.

Code cleanup related to fix for attribute 'Old; semantics is unaffected.

gcc/ada/

	* exp_ch13.adb (Expand_N_Free_Statement): After analysis, the
	new temporary has the type of its Object_Definition and the new
	occurrence of this temporary has this type as well; simplify.
	* sem_util.adb
	(Indirect_Temp_Value): Remove redundant call to Set_Etype;
	simplify.
	(Is_Access_Type_For_Indirect_Temp): Add missing body header.