make AnimatedValueXY constructor input value immutable
make AnimatedValueXY constructor input value immutable

Reviewed By: furdei

Differential Revision: D6741521

fbshipit-source-id: e8401982fbb3c3d6cd4bcc2581358fd4a5de12f9

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