Temporarily disable detach and promote

After disccusion, we decided that our migrationg will start with
detached buffer. Therefore, until we refractor both producer buffer and
detached buffer to use binder, it makes no sense to write a converter
between pdx and binder backend.

As detached buffer is neither used outside nor exposed via API, this
change should not have any negative effect.

Some tests are also disabled since after refractoring the behavior might
change, which means we have to rewrite them after refracting. Put TODOs
above them.

Change-Id: I937403a4a8ae9f3ea94718211e12326ace9060bf
Test: 'atest buffer_hub-test': passed