Update rm_rf function to force remove directories

[ayushjariyal]

closes #13269
In previous rm_rf function Uses shutil.rmtree(path, onerror=onerror), which recursively deletes everything, handling errors via onerror.

Now i update the rm_rf function to Explicitly walks the directory tree bottom-up (topdown=False) and removes files first, then subdirectories before deleting the main directory.

Now there are no more warnings after passing all tests.