Fix mislabelled polyfills for Object.entries and Object.values (#31880)

Summary:
The polyfills for `Object.entries` and `Object.values` are in a file named `Object.es7.js` when these APIs form part of ES8/ES2017 (https://en.wikipedia.org/wiki/ECMAScript#8th_Edition_–_ECMAScript_2017).

The docs (https://reactnative.dev/docs/javascript-environment#polyfills) list these correctly as ES8 so I thought it might reduce confusion if anyone starts looking into the polyfills in the future like I did.

## Changelog

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[Internal] [Fixed] - Fix filename to include correct ECMA spec

Pull Request resolved: #31880

Test Plan: All unit tests pass.

Reviewed By: yungsters

Differential Revision: D29820165

Pulled By: ShikaSD

fbshipit-source-id: 2a4eb58bed7b7a4089406665c5c9115cb1773ff6

jest/setup.js

@@ -12,7 +12,7 @@
 const MockNativeMethods = jest.requireActual('./MockNativeMethods');
 const mockComponent = jest.requireActual('./mockComponent');
 
-jest.requireActual('@react-native/polyfills/Object.es7');
+jest.requireActual('@react-native/polyfills/Object.es8');
 jest.requireActual('@react-native/polyfills/error-guard');
 
 global.__DEV__ = true;

packages/polyfills/__tests__/Object.es7-test.js → packages/polyfills/__tests__/Object.es8-test.js

@@ -10,12 +10,12 @@
 
 'use strict';
 
-describe('Object (ES7)', () => {
+describe('Object (ES8)', () => {
   beforeEach(() => {
     delete Object.entries;
     delete Object.values;
     jest.resetModules();
-    require('../Object.es7');
+    require('../Object.es8');
   });
 
   describe('Object.entries', () => {

packages/polyfills/index.js

@@ -12,5 +12,5 @@
 module.exports = () => [
   require.resolve('./console.js'),
   require.resolve('./error-guard.js'),
-  require.resolve('./Object.es7.js'),
+  require.resolve('./Object.es8.js'),
 ];