fix scale9Sprite can't culling problem
Merge pull request #6957 from andyque/fixScale9Sprite

fix scale9Sprite can't culling problem
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fixed EVENT_COME_TO_BACKGROUND has not been sent on android.
Merge pull request #6958 from Dhilan007/v3

fixed EVENT_COME_TO_BACKGROUND has not been sent on android.
[ci skip]
[ci skip]
not treat warnings as error
Merge pull request #6961 from minggo/treat-warning-as-error

not treat warnings as error
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into v3_fix
Adjust the xxtea directory structure and modify configs files for platforms