Reproduction steps:
1. Open the attached project "PlayMode_Bug.zip"
2. Open Unity Test Runner (Window -> General -> Test Runner)
3. Set test mode to PlayMode
4. Run all tests
5. In the Menu bar, click on "test" -> "SetPlaymodeStartScene"
6. Run all tests
Expected result: PlayMode tests start before and after setting PlaymodeStartScene
Actual result: PlayMode tests do not start after setting PlaymodeStartScene
Reproducible with: 1.1.27 (2019.4.29f1, 2020.3.15f2, 2021.1.16f1, 2021.2.0b6, 2022.1.0a4)
Notes: the issue also reproduces in 1.3.0-pre.3, however it seems to be working as intended in 2.0.1-epx.1