set default priority to avoid warning

when call 'scheduleUpdate' and 'unscheuleUpdate' several times in one frame, it will get warning "warning: you CANNOT change update priority in scheduled function"
Merge pull request #9050 from joewan/fix-armature-spriteframe

fix sprite frame cache, and remove unnecessary headers dependencies.
Merge pull request #9158 from zhongfq/v3

set default priority to avoid warning