AudioFlinger: Extract inner TrackHandle and RecordHandle classes

Test: atest audiorecord_tests audiotrack_tests audiorouting_tests trackplayerbase_tests audiosystem_tests
Test: atest AudioTrackTest AudioRecordTest
Test: YouTube, Camera
Bug: 288339104
Bug: 288468076
Change-Id: Ifc76e2aa4b6df801595d3ecc6b173dbc81cb9e3f
6 files changed