libstagefright: fix handling of mSampleTimeEntries and mNumSampleSizes in SampleTable. Bug: 23247055 Change-Id: I29ef59c7ff09248063714e5013f7c33f66c5eebd (cherry picked from commit 3564c4562f46bede6ef1ea716c4fd4f77e470ae8) (cherry picked from commit 108cd2dc8df55f3f2ecdfbb4bb0ae981a74b6860)