opt-functions.awk: fix comparison of limit, begin and end

opt-functions.awk: fix comparison of limit, begin and end

The function integer_range_info makes sure that, if provided, the
initial value fills in the especified range.  However, it is necessary
to convert the values to a numerical context before comparing, to make
sure awk is using arithmetical order and not lexicographical order.

gcc/ChangeLog:

      * opt-functions.awk (integer_range_info): Make sure values are in
      numeric context before operating with them.

From-SVN: r275503