Re-enable NetEQ DecoderDatabase test for Android

The test was failing because iLBC is not enabled on Android. Now, the
test is using PCM16B instead.

BUG=3343
R=tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/16519004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6143 4adac7df-926f-26a2-2b94-8c16560cd09d