For them implemeted upscaling in libyuv metrics calculation. Updated maximum number of SL in vp9 encoder to 3. Refactored names of some fields in Video_quality_check analyzer. BUG=webrtc:7095 Review-Url: https://codereview.webrtc.org/2681683003 Cr-Commit-Position: refs/heads/master@{#16625}