RCTSurface: Use async dispatch to register root shadow view
RCTSurface: Use async dispatch to register root shadow view

Summary: We don't really need sync dispatch here. We only need sequential execution of our UIManager blocks.

Reviewed By: rsnara

Differential Revision: D6367069

fbshipit-source-id: cc675aafd6c762506048bcf65c24e54080b013a5

exponentjs/react-native,janicduplessis/react-native,myntra/react-native,Bhullnatik/react-native,hoastoolshop/react-native,jevakallio/react-native,hoangpham95/react-native,jevakallio/react-native,janicduplessis/react-native,facebook/react-native,exponentjs/react-native,facebook/react-native,Bhullnatik/react-native,Bhullnatik/react-native,exponentjs/react-native,janicduplessis/react-native,jevakallio/react-native,Bhullnatik/react-native,jevakallio/react-native,exponent/react-native,facebook/react-native,hoastoolshop/react-native,javache/react-native,Bhullnatik/react-native,hoangpham95/react-native,jevakallio/react-native,javache/react-native,pandiaraj44/react-native,rickbeerendonk/react-native,pandiaraj44/react-native,rickbeerendonk/react-native,ptmt/react-native-macos,myntra/react-native,exponent/react-native,myntra/react-native,arthuralee/react-native,rickbeerendonk/react-native,rickbeerendonk/react-native,hoangpham95/react-native,hoangpham95/react-native,hoastoolshop/react-native,rickbeerendonk/react-native,myntra/react-native,myntra/react-native,exponent/react-native,dikaiosune/react-native,exponent/react-native,javache/react-native,hoangpham95/react-native,ptmt/react-native-macos,rickbeerendonk/react-native,javache/react-native,hoastoolshop/react-native,pandiaraj44/react-native,hoastoolshop/react-native,exponentjs/react-native,exponentjs/react-native,facebook/react-native,rickbeerendonk/react-native,facebook/react-native,dikaiosune/react-native,exponent/react-native,Bhullnatik/react-native,javache/react-native,hammerandchisel/react-native,janicduplessis/react-native,rickbeerendonk/react-native,janicduplessis/react-native,jevakallio/react-native,exponent/react-native,exponentjs/react-native,facebook/react-native,ptmt/react-native-macos,pandiaraj44/react-native,javache/react-native,dikaiosune/react-native,dikaiosune/react-native,arthuralee/react-native,dikaiosune/react-native,hoangpham95/react-native,exponentjs/react-native,exponent/react-native,ptmt/react-native-macos,Bhullnatik/react-native,exponent/react-native,ptmt/react-native-macos,hoastoolshop/react-native,hammerandchisel/react-native,javache/react-native,pandiaraj44/react-native,javache/react-native,ptmt/react-native-macos,pandiaraj44/react-native,myntra/react-native,dikaiosune/react-native,jevakallio/react-native,arthuralee/react-native,ptmt/react-native-macos,arthuralee/react-native,myntra/react-native,hoastoolshop/react-native,hoangpham95/react-native,jevakallio/react-native,myntra/react-native,janicduplessis/react-native,hammerandchisel/react-native,hammerandchisel/react-native,dikaiosune/react-native,janicduplessis/react-native,dikaiosune/react-native,arthuralee/react-native,pandiaraj44/react-native,ptmt/react-native-macos,hammerandchisel/react-native,facebook/react-native,hoastoolshop/react-native,myntra/react-native,Bhullnatik/react-native,hammerandchisel/react-native,exponentjs/react-native,facebook/react-native,facebook/react-native,pandiaraj44/react-native,hoangpham95/react-native,hammerandchisel/react-native,jevakallio/react-native,javache/react-native,janicduplessis/react-native,hammerandchisel/react-native,rickbeerendonk/react-native