Expected output of gdb.cp/no-dmgl-verbose.exp

[Luis Machado]

I'm trying to determine why this particular test is failing (for both 
aarch64-linux and x86_64-linux on Ubuntu 18.04/20.04) and what the 
expected outcome is.

In my case, the only symbol I see for function "f" is the following:

"f(std::__cxx11::basic_string<char, std::char_traits<char>, 
std::allocator<char> >)"

There is no "f(std::string)" nor "f(std::basic_string<char, 
std::char_traits<char>, std::allocator<char> >)" symbol.

Given we've done quite a few changes to how demangling is applied and 
how we match the names, I wonder if this test is no longer meaningful.

Does anyone know?