stagefright: Fix 24-bit WAV

 * When 24-bit output is enabled, we need to ensure that padding
   to 32 bits is done correctly.
 * Create new output buffers which conform to the correct format.

Change-Id: I5c07027ee8d3040147698c1f484b40991f943c03
ENGR00294739 coreimage, screenrecord sometimes fail when shift different video

The recorder exit because can't request encoder buffer. In this case,
sample table is not written to the mp4 file, so can't play.
Make sure the sample table is written can fix it.

Change-Id: Ia38e28d4a9a10a70bb352b03dd17a62d090c9ad4
Merge branch 'kitkat' of https://github.com/LiquidSmooth/android_frameworks_av into kitkat