Need to check that sse for non-zero mv has been set for the current block
(i.e., check that nonzero-mv is tested as a mode, so newmv_sse != UINT_MAX)
before forcing to not use zero-mv for denoising.

Also increase some thresholds (sse and sse_diff) for high noise case,
and use shift operaton instead of multiplication on a threshold computation.

Change-Id: Iae7339475d57240316b7fa8b887c4ee3c0d0dbec