Add previously released APIs to api_versions_* droidstubs

Previously, the `api_versions_*` `droidstubs` modules did not provide
a previously released API which meant that any flagged APIs that were
reverted to their previous state would be removed because there was no
previous state. That lead to problems when changing existing APIs, e.g.
to add annotations.

This change updates those module to provide the previously released
API. It uses `check_api.last_released...` as that is currently the only
way to provide a previously released API but it disabled the
compatibility checks as they are done elsewhere.

Flag: EXEMPT build fix to improve flag support
Bug: 425309457
Test: TH
Change-Id: I820ccb2cc429c0698a7b0b137fac942ed6aaaa37