gdb.gdbtk tests

[Jimmy Guo]

>They are already available.  Either download the insight+dejagnu
>snapshot or checkout the module ``insight''.

Oh, I only extract gdb + dejagnu.

>The ``GDB'' module doesn't include the gdb.gdbtk testsuites.  However,
>given that it's pretty easy to end up with that directory, a more robust
>test would be better.

I don't know if there's any easy way to maintain the modules aliases to
separate out the gdb.gdbtk test suite from mainline gdb tree.  As of
3/21 that's not the case (or I wouldn't see the test suite).  Keeping it
in the tree would be fine provided that a better bypass than the current
(let TCL complain about 'cd' failure and dump call trace).  For now,
locally, I'm adding gdb.gdbtk to the skip list in site.exp.

- Jimmy