Import hooks should be updated for newer Python versions

[vyasr]

Describe the current behavior
The import hooks in https://github.com/googlecolab/colabtools/tree/main/google/colab/_import_hooks are written for pre-Python 3.4. The find_module method was replaced by find_spec in Python 3.4, at which point find_module was also deprecated. importlib.util.find_spec works around the possibility of old finders by simply ignoring those that lack this method, but this means that the modules that colab is patching will not benefit from newer functionality in importlib or related modules that relies on this function. Moreover, new finder implementations may not be written around this and may expect find_spec to be defined on all loaders in sys.meta_path, resulting in runtime errors. A concrete example of this is in numba-cuda, which uses a custom finder to provide backwards compatibility with the legacy cuda target in numba (see this post for more information).

Describe the expected behavior
Finders should be able to rely on all elements of sys.meta_path implementing find_spec

What web browser you are using
Firefox

Additional context
The issue is reproducible with this gist: https://colab.research.google.com/gist/vyasr/9ef26e1073037a15d08fc847798f39b2/colab_meta_path.ipynb

[colaboratory-team]

Thanks for the report, tracking internally in b/383879146