Fix int() builtin with range type gdb.Value objects.

Fix int() builtin with range type gdb.Value objects.

Consider the following variable:

    type Small is range -128 .. 127;
    SR : Small := 48;

Trying to get its value as an integer within Python code yields:

    (gdb) python sr = gdb.parse_and_eval('sr')
    (gdb) python print int(sr)
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    gdb.error: Cannot convert value to int.
    Error while executing Python code.

This is happening because our variable is a range type, and
py-value's is_intlike does not handle TYPE_CODE_RANGE. This
patch fixes this.

gdb/ChangeLog:

        * python/py-value.c (is_intlike): Add TYPE_CODE_RANGE handling.

gdb/testsuite/ChangeLog:

        * gdb.ada/py_range: New testcase.