Fixed retina/contentScale position errors for iPhone 6+ devices in EditBox.

Problem is that factor was 1.0 or 2.0 until iOS 8 introduced 3.0.
Merge branch 'v3' into fixEditBox_v3
fix EditBox move animation position is wrong on iPhone6 Plus
Merge pull request #9410 from andyque/fixEditBox_v3

Fix edit box v3