Delete stale Virtualization image files

Delete all files and directories under
/data/misc/virtualizationservice at boot. Originally they were owned
by the virtualizationservice user; we now run as system, and don't
have permission to remove them after boot.

Bug: 230056726
Test: Create fake stale dir+file, see them deleted
Change-Id: I5ff7d055aeeb25ba7693e50876d6b8a830c4bf51
(cherry picked from commit 34ee0c93)