Summary:
X-link: https://github.com/facebook/react-native/pull/43752
Gentest tests started failing because Chrome changed behavior of overflowed align-content container. Spec says should fallback to "safe center", which is really just "start", instead of previous "center" behavior. This changes behavior accordingly.
There is one bit where I think we are doing the wrong thing wrt alignment of flex start vs start (which we don't support yet), but couldn't repro a failing chrome test.
Changelog: [Internal]
Reviewed By: joevilches
Differential Revision: D55617689
fbshipit-source-id: 08f23d198c75f2c2f51ccaa8795289e6e4a92cb8