Use the updated best rd cost for transform block search
Use the updated best rd cost for transform block search

The compression performance change is +/-0.01% for both speed 0/1.
Locally tested the encoding speed:

ped_1080p 150 frames speed 0
79544 b/f 41.339 dB 503072 ms ->
79566 b/f 41.338 dB 493009 ms.

speed 1
79789 b/f 41.152 dB 104583 ms ->
79770 b/f 41.153 dB 102607 ms

Change-Id: Ief200b613608643e5708cebe979982eb4a84831b

webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx