Add static-threshold skipping in non-rd mode

Add static-threshold skipping in non-rd mode

Added a skipping test in non-rd inter-mode. After interpolation
prediction step, the residuals are tested to see if they will be
quantized to 0 based on modeling between spatial domain and
frequency domain.

Set static-thresh to 800 for >=720p and 300 for <720p, rtc set
tests showed
1. Speed 5, psnr: -0.514%; ssim: -1.748%;
   speedup on related clips: 5% -11%
2. Speed 6, psbr: -0.628%; ssim: -1.637%;
   speedup on related clips: 4% - 9%

Change-Id: I62fbf26bc043ecd2b584f255f1a4ee5ab52bfcf3