Eliminate unnecessary copies of node style objects
Eliminate unnecessary copies of node style objects

Summary:
@public

`YGNode.getStyle()` returns a reference to the enclosed `YGStyle` member. Assigning to a local copies unnecessarily.

Having eliminated the copy, we can also safely remove calls to `YGNode.setStyle()`, eliminating another copy.

Reviewed By: astreet

Differential Revision: D9083336

fbshipit-source-id: df8b603b5cc0b974cf5dd434c71956be4548e583

hoangpham95/react-native,myntra/react-native,hoangpham95/react-native,exponent/react-native,exponent/react-native,exponent/react-native,javache/react-native,exponent/react-native,javache/react-native,janicduplessis/react-native,facebook/react-native,janicduplessis/react-native,hammerandchisel/react-native,exponent/react-native,myntra/react-native,janicduplessis/react-native,exponentjs/react-native,myntra/react-native,hammerandchisel/react-native,exponentjs/react-native,hoangpham95/react-native,hoangpham95/react-native,exponentjs/react-native,pandiaraj44/react-native,pandiaraj44/react-native,pandiaraj44/react-native,exponent/react-native,hammerandchisel/react-native,facebook/react-native,arthuralee/react-native,hammerandchisel/react-native,myntra/react-native,facebook/react-native,janicduplessis/react-native,javache/react-native,hoangpham95/react-native,facebook/react-native,facebook/react-native,javache/react-native,janicduplessis/react-native,exponentjs/react-native,exponentjs/react-native,exponentjs/react-native,hammerandchisel/react-native,exponent/react-native,javache/react-native,hammerandchisel/react-native,arthuralee/react-native,exponent/react-native,myntra/react-native,pandiaraj44/react-native,facebook/react-native,facebook/react-native,javache/react-native,arthuralee/react-native,pandiaraj44/react-native,javache/react-native,hoangpham95/react-native,myntra/react-native,janicduplessis/react-native,pandiaraj44/react-native,exponentjs/react-native,exponentjs/react-native,hoangpham95/react-native,janicduplessis/react-native,hammerandchisel/react-native,arthuralee/react-native,javache/react-native,janicduplessis/react-native,facebook/react-native,hoangpham95/react-native,pandiaraj44/react-native,pandiaraj44/react-native,javache/react-native,facebook/react-native,hammerandchisel/react-native,myntra/react-native,myntra/react-native,arthuralee/react-native,myntra/react-native