Summary:
The standard says that zIndex should only be defined for non-`static` positioned views. This diff implements it.
For now, it actually enables zIndex for all views in RN because there is no way to specify `position: static` but we will give that ability by changing Flow definitions in future diffs in a couple of weeks (to ensure OTA safety).
Changelog: [Internal] Fabric-specific internal change.
Reviewed By: sammy-SC
Differential Revision: D23559447
fbshipit-source-id: 20ea10c9349de2c5b1adea5735324a8f57150695
Valentin Shergin
4d920fe7c9