How to reset build scenes after running unit tests?

I'm trying to set up a system where each unit test is a separate scene. To load a scene at runtime, I need to add them to EditorBuildSetting.scene. I currently do this by using the PrebuildSetup attribute.

This works fine, however I would like to reset the original build settings after the unit tests were completed. I tried using the PostBuildSetup attribute to implement a Cleanup method that resets the build settings scenes to the original list, but between the setup and the cleanup functions, the list I store becomes null:

 [PrebuildSetup(typeof(RenderPerformancePrebuildSetup))]
 [PostBuildCleanup(typeof(RenderPerformancePostBuildCleanup))]
 public class RenderPerformanceTests 
 {
     [PerformanceTest]
     public void SimplePerformanceTest()
     {
        // do stuff
     }
 }
 
 public class RenderPerformancePrebuildSetup : IPrebuildSetup
 {
     public static Scene[] buildSettingsScenes;
     
     public void Setup()
     {
         buildSettingsScenes = EditorBuildSettings.scenes;
         EditorBuildSettings.scenes = // list of test scenes;
     }
 }
 
 public class RenderPerformancePostBuildCleanup : IPostBuildCleanup
 {
     public void Cleanup()
     {
         EditorBuildSettings.scenes = RenderPerformancePrebuildSetup.buildSettingsScenes;
     }
 }