Remove much dead code from ceval.c

The descr changes moved the dispatch for calling objects from
call_object() in ceval.c to PyObject_Call() in abstract.c.
call_object() and the many functions it used in ceval.c were no longer
used, but were not removed.

Rename meth_call() as PyCFunction_Call() so that it can be called by
the CALL_FUNCTION opcode in ceval.c.

Also, fix error message that referred to PyEval_EvalCodeEx() by its
old name eval_code2().  (I'll probably refer to it by its old name,
too.)