Call to Scope returns an Entity_Id, not just Node_Id. This patch refines
the types in two occurrences of a call to Scope as an initial value.

Code cleanup; semantics is unaffected.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* exp_ch4.adb (User_Defined_Primitive_Equality_Op): Refine type
	of a local variable.
	* exp_dbug.adb (Scope_Contains): Refine all types from Node_Id
	to Entity_Id; rename parameters to match those of the
	Scope_Within routine (which is similar but not the same); also,
	simplify an OR ELSE into a membership test.