For nonrd_pickmode: if early_term is set there should be
no need to include UV in rdcost (when color_sensitivity is set).

Neutral change on RTC and RTC_derf metrics, for speed >= 5.
No change for ytlive metrics.

Very small speed gain (~0.5%) on some clips with strong color content.

Change-Id: Ifc00928ecd935fc71e94935ceef0ae7481249f07