docs: public ReferenceType getFirstCommonSuperclass(ReferenceType a, ReferenceType b) throws ClassNotFoundException {
          // Easy case: same types
          if (a.equals(b)) {
              return a;
          }
  
          ReferenceType answer = checkFirstCommonSuperclassQueryCache(a, b);
          if (answer == null) {
              answer = computeFirstCommonSuperclassOfReferenceTypes(a, b);
              putFirstCommonSuperclassQueryCache(a, b, answer);
          }
          return answer;
      }