Revert changes to react-devtools-inline Webpack config from PR facebook#22760 (facebook#22961)

Author: Brian Vaughn

packages/react-devtools-inline/webpack.config.js

@@ -33,14 +33,6 @@ const babelOptions = {
   ),
 };
 
-const builtModulesDir = resolve(
-  __dirname,
-  '..',
-  '..',
-  'build',
-  'oss-experimental',
-);
-
 module.exports = {
   mode: __DEV__ ? 'development' : 'production',
   devtool: __DEV__ ? 'eval-cheap-source-map' : 'source-map',
@@ -57,10 +49,10 @@ module.exports = {
     libraryTarget: 'commonjs2',
   },
   externals: {
-    react: resolve(builtModulesDir, 'react'),
-    'react-dom': resolve(builtModulesDir, 'react-dom/unstable_testing'),
-    'react-is': resolve(builtModulesDir, 'react-is'),
-    scheduler: resolve(builtModulesDir, 'scheduler'),
+    react: 'react',
+    'react-dom': 'react-dom',
+    'react-is': 'react-is',
+    scheduler: 'scheduler',
   },
   node: {
     // source-maps package has a dependency on 'fs'