Merge from Widevine repo of http://go/wvgerrit/49820
Devices with baked-in DRM certs cannot be reprovisioned. As such, we
must protect them against being unprovisioned. Currently, our unit
tests break such devices by attempting to unprovision them. This patch
adds code to block the Unprovision() call on these devices.
Bug: 69264798
Test: CE CDM Unit Tests
Test: tested as part of http://go/ag/4674759
Change-Id: I49322dcb2d3d5c7953e870eb91a9e0b978d4dabe
240652afcf