stagefright: Use HW AAC decoder in ACodec if requested

 * testHLS is failing due to parsing issues with the AAC track
 * Switch to the more robust HW decoder for HLS as well.

Change-Id: I2299266d5f2d8cb0ac457241e4f1d0f4ef87ea05
Merge "stagefright: Use HW AAC decoder in ACodec if requested" into du44