[lldb] Print mangled names with verbose break list (#84071)

When debugging LLDB itself, it can often be useful to know the mangled
name of the function where a breakpoint is set. Since the `--verbose`
setting of `break --list` is aimed at debugging LLDB, this patch makes
it so that the mangled name is also printed in that mode.

Note about testing: since mangling is not the same on Windows and Linux,
the test refrains from hardcoding mangled names.