TestFileHandle.py: relax exception type checks

the exceptions returned differ between swig4 (TypeError) and swig<=3
(NotImplementedError). Just check for the base Exception class instead.

Theoretically we could switch on the swig version and expect the precise
type directly, but checking the exact type does not seem that important.

Thanks to Raphael for helping me figure this out.

llvm-svn: 374322