MEPG4Writer:return track errors to clients

Error returned by track threads would be passed to clients.
Cleanup misuse of types in error values.
Don't bubble up fsync error.
Catch write/seek error while writing initial boxes.

Bug: 157926677
Bug: 157291505

Test: android.media.cts.MediaMuxerTest
Test: android.mediav2.cts.MuxerTest
Test: android.mediav2.cts.MuxerUnitTest
Test: android.media.cts.MediaRecorderTest

Change-Id: I17d3e5746c3284b49db94ce63c0b5d8c97e7bc9c