read_tile_info: Validate context_update_tile_id.
read_tile_info: Validate context_update_tile_id.

context_update_tile_id should be less than the number of tiles.

BUG=aomedia:2090
BUG=oss-fuzz:9720

Change-Id: Ic02900ec50dc8f4af6dea3678f49e1bec41a770c

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom