Data Analyzer CPU-only test is using GPU when available

[mingxin-zheng]

Describe the bug

MONAI/tests/test_auto3dseg.py

Line 187 in 9b4c235

self.datalist_file, self.dataroot_dir, output_path=self.datastat_file, label_key=label_key

device is not specified to cpu after the PR that changes default device to cuda

Expected behavior
CPU-only test should be using CPU.

[wyli]

addressed by #6278