This patch fixes the checkpoint restore option in the example of C++
configuration (util/cxx_config).
The fix introduces a call to config_manager->startup() (which calls startup
on all SimObjects managed by that manager) to replicate the loop of
SimObject::startup calls in src/python/m5/simulate.py::simulate guarded by
need_startup. As util/cxx_config/main.cc is a C++ analogue of
src/python/mt/simulate.py, it should make a similar set of calls.
27b7b9e561