SDK / exoplayer

When the decoder output buffer was partially read, a call to
Codec.getOutputBuffer() was returning the same buffer, but with the
position reset to 0. The reason was that, in
Codec.maybeDequeueAndSetOutputBuffer(), mediaCodec.getOutputBuffer()
was called with the same buffer index (L350 in old rev), even though
there was already a buffer available (outputBufferIndex >=0). This
change avoids calling mediaCodec.getOutputBuffer() if the previous
buffer has not been released.

#minor-release

PiperOrigin-RevId: 424612197