[Bug demangler/79976] long list of demangle failures

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79976

--- Comment #4 from Pedro Alves <palves at redhat dot com> ---
That's a good point.  Maybe a mangling/demangling hash/cache would help with
that, though can't beat 0 work.