[ASL] Parsing error for asllib/tests/ASLTypingReference.t/TypingRule.ApproxBottomTop.asl

Reproduce via:
```sh
aslref test/ASL/ASLTypingReference.t/TypingRule.ApproxBottomTop.asl
File test/ASL/ASLTypingReference.t/TypingRule.ApproxBottomTop.asl,
  line 10, characters 4 to 30:
    var x : integer{a..b} = a;
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
ASL Type error: a subtype of integer {a..b} was expected,
  provided integer {1..10}.

```