Merge pull request #8884 from Dhilan007/v3-labelfix

Rolling back text color of system font on Linux
Update cocos2d basic lua files and LabelTestNew.lua
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into v3_new_spine
Merge pull request #8887 from samuele3hu/v3_new_spine

Update cocos2d basic lua files and LabelTestNew.lua