Make 'app' users/groups more accurate

In an attempt to make bionic's reporting of users and groups more
accurate, this change makes the user / group functions do the
following:

1) Fail to query a uid/gid for a secondary user when the uid/gid
   doesn't exist.  Currently bionic would return successfully but with
   a empty string for the name.
2) Fail to query a platform uid/gid, except a limited pre-allocated
   set for a secondary user, as these are not used by second users.
3) Fail to query uids for all users for the GID-only app ranges:
   CACHE_GID, EXT_GID, EXT_CACHE_GID, SHARED_GID.
4) Fail to query gids in SHARED_GID range for secondary users, as
   these GIDs are only allocated for the first user.
5) Use "u#_a#_ext" and u#_a#_ext_cache" for EXT_GID and EXT_CACHE_GID
   ranges.  This both allows querying based on these names and
   returning these names for the appropriate uids/gids.

This also consolidates the tests for better readability.

Test: these unit tests, boot

Change-Id: I59a1af0792e7806d423439582e56ce7f9f801c94

0 files changed, 0 insertions, 0 deletions