AudioFlinger: refine latency computation if track is drained

Use server timestamp if track has no actively presented frames
(i.e. drained). Sometimes track frames may not have reached the HAL.

Test: audioflinger dumpsys with BT audio
Bug: 80447764
Change-Id: Iffc52f4cfcbadd419c6b6ccfa278e0712f3af4af
4 files changed