C++: Remove unnecessary cast.

Author: MathiasVP

cpp/ql/test/library-tests/types/sizeof/sizeof.ql

@@ -3,7 +3,7 @@ import cpp
 from SizeofOperator sto, string elemDesc, Element e
 where
   elemDesc = "SizeofOperator.getTypeOperand()" and
-  e = sto.(SizeofOperator).getTypeOperand()
+  e = sto.getTypeOperand()
   or
   elemDesc = "SizeofExprOperator.getExprOperand()" and
   e = sto.(SizeofExprOperator).getExprOperand()