Enable more cpp_locals tests (GH-4320)

Turns out that typeid() and C++ operators already work with "cpp_locals".

tests/errors/w_uninitialized_cpp.pyx

 # cython: warn.maybe_uninitialized=True
 # mode: error
-# tag: cpp, werror, no-cpp-locals
-# FIXME - no-cpp-locals should work
+# tag: cpp, werror
 
 from cython.operator import typeid
 

tests/run/cpp_operators.pyx

 # mode: run
 # tag: cpp, werror
-# tag: no-cpp-locals
-# FIXME - cpp_locals should work but doesn't
 
 from __future__ import division
 

tests/run/fused_cpp.pyx

-# tag: cpp, no-cpp-locals
-# FIXME (or at least investigate) - cpp_locals should probably work
+# tag: cpp
 
 cimport cython
 from libcpp.vector cimport vector