[libstdc++] Update comments in testsuite files, add dummy tool file.

[Gabriel Dos Reis]

Benjamin Kosnik <bkoz@redhat.com> writes:

| >| No, I think /we/ got the wrong file name, back when all this was put
| >| into place.
| >
| >Hmm, when I put the DejaGnu testing framework into place, the file was
| >named libstdc++.exp.  It got renamed to the current name after some
| >complete rewrite. 
| 
| Probably my fault.

hey, I didn't intend to blame anyone!

-- Gaby