Python: Rewrite test for __add__ special method

Co-authored-by: yoff <lerchedahl@gmail.com>

Author: RasmusWL

python/ql/test/experimental/library-tests/CallGraph/code/class_special_methods.py

@@ -38,9 +38,9 @@ def wat(self):
 print("\n! b2")
 b2 = Base(2) # $ tt=Base.__init__
 
-# __add__ is called
-b + b2
-b + 100
+
+b + b2 # $ MISSING: tt=Base.__add__
+b + 100 # $ MISSING: tt=Base.__add__
 
 
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