Summary:
If the first element of a line is not contributing (e.g. position absolute), an additional gap will be added to the line, because the first gap element of the line is never identified (wrong start index).
Fix: raise the index of the first line element until we find an element that is contributing to the line.
Pull Request resolved: https://github.com/facebook/yoga/pull/1408
Reviewed By: yungsters
Differential Revision: D49722065
Pulled By: NickGerleman
fbshipit-source-id: 1068cb0b11ae4b04ec8d063e70540cce06181d5a
07cabca526