Preserve Platform.select initializer side effects

[mfkrause]

Summary

Metro replaces Platform.select({...}) with the selected property during production transforms. JavaScript evaluates every object property initializer before calling Platform.select, so this can silently remove side effects from non-selected properties.

For example:

Platform.select({
  ios: selected(),
  android: discarded(),
});

JavaScript would run both side effects, selected() and discarded(). The plugin's current behavior removes discarded however.

This fix preserves both side effects by testing for purity.

Changelog:

 - **[Fix]**: Preserve side effects from discarded `Platform.select` property initializers

Test plan

Added a regression test, and ensured existing tests, linter and formatter pass.

[vzaidman]

why is the logic slightly different from react/react-native#58350 ?

edit: De Morgan's Rule

[meta-codesync]

@vzaidman has imported this pull request. If you are a Meta employee, you can view this in D119065903.

[meta-codesync]

@vzaidman merged this pull request in d5d4e95.

[facebook-github-tools]

This pull request has been reverted by 4c9b1cb.