Add a test of .pth handling. #339

Job	Run time
Pre-commit checks / Pre-commit Checks	10s
Unit tests (macOS-Xcode, 3.10)	5m 6s
Unit tests (macOS-Xcode, 3.11)	5m 15s
Unit tests (macOS-app, 3.9)	3m 5s
Unit tests (macOS-Xcode, 3.12)	4m 8s
Unit tests (macOS-Xcode, 3.13)	3m 9s
Unit tests (macOS-Xcode, 3.9)	3m 57s
Unit tests (macOS-app, 3.12)	2m 33s
Unit tests (linux-flatpak, 3.10)	4m 55s
Unit tests (linux-flatpak, 3.9)	5m 22s
Unit tests (macOS-app, 3.10)	2m 53s
Unit tests (macOS-app, 3.11)	1s
Unit tests (macOS-app, 3.13)	1s
Unit tests (linux-flatpak, 3.11)	5m 59s
Unit tests (linux-flatpak, 3.12)	5m 28s
Unit tests (windows-VisualStudio, 3.10)	4m 23s
Unit tests (linux-flatpak, 3.13)	6m 8s
Unit tests (windows-VisualStudio, 3.9)	5m 18s
Unit tests (windows-VisualStudio, 3.11)	5m 5s
Unit tests (windows-VisualStudio, 3.12)	4m 59s
Unit tests (windows-app, 3.9)	47s
Unit tests (windows-app, 3.13)	5m 21s
Unit tests (iOS, 3.9)	10m 29s
Unit tests (windows-VisualStudio, 3.13)	5m 0s
Unit tests (iOS, 3.13)	8m 39s
Unit tests (windows-app, 3.10)	3m 41s
Unit tests (iOS, 3.11)	1s
Unit tests (windows-app, 3.11)	4m 11s
Unit tests (windows-app, 3.12)	4m 10s
Unit tests (iOS, 3.10)	7m 38s
Unit tests (iOS, 3.12)	1s
Unit tests (android, 3.9)	6m 11s
Unit tests (android, 3.13)	5m 40s
Unit tests (android, 3.10)	7m 18s
Unit tests (android, 3.12)	7m 4s
Unit tests (android, 3.11)	6m 57s
Unit tests (linux-system, system, ubuntu-latest, sudo apt update -y && sudo apt install -y --no-i...	42s
	2h 41m 45s

Provide feedback