Adds performance test for callbacks: 1) std::function,
2) (target->*selector)(), 3) simulate new api of Scheduler
Removes unused enum in PerformaceCallbackTest
Merge branch 'develop' into perf-callback

Conflicts:
	build/cocos2d_tests.xcodeproj/project.pbxproj
Merge pull request #6291 from dumganhar/perf-callback

Adds performance test for callbacks: 1) std::function,2) (target->*selector)(), 3) simulate new api of Scheduler