[RFA/testsuite/ada] Add gdb.ada subdirectory + Makefile & Ada project file

[Andrew Cagney]

Ok.

2004-03-29  J. Brobecker  <brobecker@gnat.com>

         * gdb.ada: New subdirectory.
         * gdb.ada/Makefile.in: New file.
         * gdb.ada/gnat_ada.gpr.in: New file.