Exclude default styles from <compat.native>

* Don't include web defaults of `position:static` and
  `boxSizing:content-box` in the transformed styles when using
  `<compat.native>`. Simply transform the input styles.
* Don't include web defaults on `<br />`.

Author: necolas

packages/react-strict-dom/src/native/compat.js

@@ -10,6 +10,7 @@
 import type { StrictProps } from '../types/StrictProps';
 
 import * as React from 'react';
+
 // $FlowFixMe[nonstrict-import]
 import { createStrictDOMComponent as createStrict } from './modules/createStrictDOMComponent';
 // $FlowFixMe[nonstrict-import]