PATCH: Update libiberty/testsuite/demangle-expected

[DJ Delorie]

> For this particular case where we have a failed testcase which is
> imported from another part of gcc, is keeping it in sync with the
> original source an obvious change?

All testsuite changes require approval.

> Or should we require they should be updated at the same time?

I think it's a good idea to keep track of changes in the C++
demangler, and keep the libiberty testsuite up to date.  I just don't
think that blindly updating it is ever correct.  The whole point of a
testsuite is to ensure that the code is doing the right thing; every
change needs to be reviewed to make sure that the new results are more
correct than the old results; automatic changes to testsuites defeat
their whole purpose.