Reproduction steps:
1. Open "optimization_tests.zip" project
2. "Preferences" -> "General" -> "Code Optimization on Startup" -> "Debug" (If it was already "Debug", switch to "Release" and back again)
3. In the Main Editor window, at the bottom right corner, press the Bug icon -> "Switch to release mode"
4. Wait for it to re-compile
5. Re-open the project
6. "Window" -> "General" -> "Test Runner"
7. Run EditMode test "IsDebugAssembly"

Expected Result: Test passes
Actual Result: Test fails as the script/assembly has not been recompiled at startup

Reproduced with: 2020.1.0a6, 2020.1.0a4
Could not reproduce on, because feature implemented only on 2020.1.0a4: 2020.1.0a3, 2020.1.0a1, 2019.3.0b4, 2019.2.7f2, 2018.4.10f1, 2017.4.32f1

Note:
To fix, a manual Reimport of the "Tests.cs" script is needed