Steps to reproduce:
1. Open the attached project
2. Go to "Assets" > "Test" > "Test" > "Test" in the Project window
3. Right-click a .obj file and select Reimport

Expected results: file is imported in about 5 minutes
Actual result: file import never finishes

Reproducible with: 2018.4.33f1, 2019.4.23f1, 2020.3.3f1, 2021.2.0a11

Notes:
- To reproduce the issue you may need to reimport multiple times (reproduces inconsistently), should not take more than 5 reimports to reproduce
- Tested and reproduced using Russian, Deutsch (Deutschland), and Chinese language keyboards
- Tested but could not reproduce using Lithuanian, English (United States) language keyboards
- Same file in .fbx format imports in less than 5 minutes
- Only reproduce when importing to a subfolder of Assets (reproduces when importing to "Assets\test\", does not reproduce when importing to "Assets\")
- Sometimes import may finish after about 0.5-1 hour (In versions where it does not reproduce import of the same file takes only about 2 minutes)
- Tested with other similar size .obj file, import took only about 2 minutes