Go: fix overload functions with polymorphic

This bug can be re-produced when one of overloaded functions accepts a pointer to BaseClass but a pointer to DerivedClass is passed, and finally leads to application's crashing.

Test case is also included.
@ojwb This file is auto-generated and shouldn't be here at all.
Please refer this commit https://github.com/swig/swig/commit/9834a69c18478fdc3b78ba52faabf7c551aef531
The current state can be safely merged and if it is not appropriate I can make a merge with current Master branch.