test: python windows dll pattern tests

In #4023, @jananir640 has added a pattern to detect python3 DLLs for windows correctly.

It would be good to have a pair of tests using this new pattern:

1. Add some mapping test data to https://github.com/intel/cve-bin-tool/blob/main/test/test_data/python.py that triggers this pattern
2. Add a file test, potentially using https://s3.amazonaws.com/ddagent-windows-stable/datadog-agent-7-latest.amd64.msi which was the file that originally triggered the bug

This should be doable by a new user, so I'm flagging it as a good first issue. But now that we're not in the middle of gsoc applications (and thus trying to save good first issues for gsoc applicants), anyone should feel free to work on this.