21.9: new volume debugger options
Updating preInclude.VolumeDebugger.py to allow the volume checked to be set based on environment variables. The motivation is that in ITKLayouts CI pipelines, a check can be performed on which files have changed, and use this to decide whether to run the volume debugger on only pixel, only strips, or both.
Adding also a new option to RunUpgradeTests.py to include the VolumeDebugger for the appropriate test configuration.