c++: avoid using the obsolete names

* data/skeletons/c++.m4: Don't define obsolete identifiers in the case
of glr2.cc.  Let's not start with technical debt.
* data/skeletons/glr2.cc, data/skeletons/lalr1.cc,
* data/skeletons/variant.hh: Use token_kind_type, not token_type.
* tests/c++.at, tests/local.at: Use value_type, not semantic_type.
6 files changed