improve VirtualizedList error message (#25973)
improve VirtualizedList error message (#25973)

Summary:
Motivation: when you receive error like `scrollToIndex out of range: 5 vs -1` it's not immediately clear if I requested 5 or -1. This will make the error a little easier to understand.

## Changelog

not needed
Pull Request resolved: https://github.com/facebook/react-native/pull/25973

Test Plan: not needed, tests must pass

Differential Revision: D16708522

Pulled By: osdnk

fbshipit-source-id: 8dfcbd95ff0f42805dbe32cd57969a93aea55add

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