Clean up test infrastructure

o Update known failures for fft16 to match reality.
o Include info about tests that unexpectedly passed and tests that
  failed that weren't expected to fail.
o Add TestOneFFT to run one FFT test (forward, inverse, or both) and
  use it for all test programs instead of having one for each.

BUG=
R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2929004

git-svn-id: http://webrtc.googlecode.com/svn/deps/third_party/openmax@5035 4adac7df-926f-26a2-2b94-8c16560cd09d