********************************************************************************
###@###.### 2001-12-19

With Build:
j2sdk-1_4_0-rc-bin-b89-win-06_dec_2001

Problem Description:
The concrete_base_type() returns null value while invoking the method on valuetype typecode object. This method should return the TypeCode object of concrete base type which is specified in valuetype typecode created from orb.

Test Source Code:
Attached with this bug.
********************************************************************************