Expose acquire_fence though ConsumerQueue::Dequeue

The current compositor implementation will be refactored to use
BufferHubQueue instead of ad-hoc BufferHub operations. We need this to
expose release_fence to compositor so that it can wait for buffers
to become avaiable by checking fence properly.

Bug: 36033302
Bug: 36148608
Test: Built and ran buffer_hub_queue-test
Change-Id: I75cfcb02e06a4b9e7e89b89690ca2d92ee09a678