main/aom: upgrade to 3.5.0

https://aomedia.googlesource.com/aom/+/refs/tags/v3.5.0/CHANGELOG

    * Speed-up multithreaded encoding for good quality mode for larger number of
      threads through frame parallel encoding:
      o 30-34% encode time reduction for 1080p, 16 threads, 1x1 tile
        configuration (tile_rows x tile_columns)
      o 18-28% encode time reduction for 1080p, 16 threads, 2x4 tile
        configuration
      o 18-20% encode time reduction for 2160p, 32 threads, 2x4 tile
        configuration