When a derived class has a public 'using Base::method;' that names a
base class member template with no SWIG visible (%template) instantiations
and the same class declares a protected concrete override of the same
name, SWIG segfaulted while finalising the symbol table overload chain.
Fix and add a regression test cpp11_using_member_template mirroring the original
reproducer from #3415.
Closes#3416
Julien Marrec