Hide importlib stack in visualization?

[anntzer]

Since the switch to pure-python importlib, importing a module brings in a bunch of functions to the call stack (_find_and_load, _find_and_load_unlocked,_load_unlocked,exec_module,_call_with_frames_removed`, etc.) Typically this shouldn't be an issue, except when profiling a startup where import time is significant. Perhaps these should be special-cased and hidden away (like for traceback display)?