Upstream Yoga Measurement Patches

[NickGerleman]

We patched Yoga to change measurement behavior with microsoft/react-native-macos#100. This requires us to maintain a separate copy of Yoga in react-native-windows. We should upstream our patch into facebook/react-native.

@acoates-ms was of the opinion we may want to put the change behind a preprocessor definition we would enable in RNW to avoid changing iOS/Android behavior.

[woehrl01]

@NickGerleman Hi, I just stumbled over that open issue. As I heavily contributed to https://github.com/facebook/yoga a few years ago, my recommendation would be to use YGExperimentalFeature* + YGConfigSetExperimentalFeatureEnabled for that, as it doesn't require a preprocessor. We actually added that behavior exactly for those cases.

You simply extend the sequence in YGEnum.h + adding the logic around that. You could then enable that behavior only for affected (sub-)trees.