White box / selftest directory

[Andrew Cagney]

FYI,

Fernando and I had a bit of a chin wag about this one.  As soon as Joel 
has a test case, there can be a gdb.gdb testsuite directory.

The objective is to use it to test internal interfaces.  For instace, 
ui-file.h defines a file i/o interface.  A ui-file test would exercise 
the interface but NOT poke around in the internals.  That way we've 
better tests on our key interfaces without pinning down or stagnating 
the implementation.

enjoy,
Andrew