Use sysconfig for Python platform discovery

distutils is deprecated and slated for removal
in Python 3.12. sysconfig is the canonical
source for platform information.

CMake/vtkWheelPreparation.cmake

@@ -20,7 +20,7 @@ set_property(GLOBAL PROPERTY _vtk_python_soabi "${Python3_SOABI}")
 
 execute_process(
   COMMAND "${Python3_EXECUTABLE}"
-          -c "from distutils import util; print(util.get_platform())"
+          -c "from sysconfig import get_platform; print(get_platform())"
   OUTPUT_VARIABLE python_platform
   ERROR_VARIABLE  err
   RESULT_VARIABLE res