Fix Out of Bounds Read in AAVCAssembler

Fixed Out of Bounds Read in dropFramesUntilIframe Function in
AAVCAssembler.
Added missing bound checks in pickStartSeq function of AHEVCAssembler.

Manual cherry-pick of pa/2300853.

Bug: 230630526

Change-Id: Ia9d0b172d0d09e3bf80a3b4bfc5d1125ac00264d
Test: Manual, See bug for repro steps.
(cherry picked from commit fa29e9f0320f29448f8481e4b50de7ac65297558)
Merged-In: Ia9d0b172d0d09e3bf80a3b4bfc5d1125ac00264d
(cherry picked from commit 3066b1410d87cc8f320cf8dd7eb7705172773919)
Merged-In: Ia9d0b172d0d09e3bf80a3b4bfc5d1125ac00264d
2 files changed