Previously, META/apex_info.pb contained only /system/apex apexes. Now,
it has all apexes from all possible partitions.
The main purpose of this file is to caculate the decompressed apex size
when applying OTA. Hence it should have all apexes, not just system
apexes.
Bug: 320228659
Test: m dist # check META/apex_info.pb
Change-Id: I3428dc502e4fe3336d1fc5ca941f1fbc332985cd