Add test for user data rollback.

The test is currently marked @Ignore because we haven't implemented
support for user data rollback yet.

Test: atest RollbackTest (selinux disabled)
Test: atest RollbackTest fails without the @Ignore.
Bug: 112431924
Change-Id: I3f7906001c932969bdf2125d198f379bf35a99fb
5 files changed