Fix test signals for order 1 tests, and enable these tests.

o For signal type 2, the expected FFT was incorrect; it should be all zeros
  because the input is all zeroes.
o For signal type 3, the expected FFT was incorrect.
o A few optimizations to remove round-off errors in computing sin(pi).

BUG=
R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2819004

git-svn-id: http://webrtc.googlecode.com/svn/deps/third_party/openmax@5034 4adac7df-926f-26a2-2b94-8c16560cd09d