Don't let an expression be put into its own list of split quantifiers, to prevent infinite loops

Author: jaylorch

Source/Dafny/DafnyAst.cs

@@ -8870,8 +8870,10 @@ public List<Expression> SplitQuantifier {
         return _SplitQuantifier;
       }
       set {
-        _SplitQuantifier = value;
-        SplitQuantifierExpression = SplitQuantifierToExpression();
+        if (!value.Contains(this)) {
+          _SplitQuantifier = value;
+          SplitQuantifierExpression = SplitQuantifierToExpression();
+        }
       }
     }