Fix SnapshotTest crash

For Android 12 vendor project, SnapshotTestEnvironment setup is skipped. So, test_device is not initialized, which will cause other tests to fail.

Change-Id: I6ce6a9e7ea2c210e25c2a5ffadaaa6348086ea7f
BUG:350678717
Test:run vts -m vts_libsnapshot_test
1 file changed