Fix off by one reading build id.

Update unit tests and add new build id displaying in offline unwinds.

Bug: 129873279

Test: All unit tests pass.
Test: Verify that debuggerd displays build id properly.
Change-Id: I97f4a204842447a20c812f535a458155b937d5e1
Merged-In: I97f4a204842447a20c812f535a458155b937d5e1
(cherry picked from commit 1760b457)