Don't transform node_modules in open source

Summary: We aren't ignoring node_modules so we apply our transform on *all of them*.

See facebook#2942 and facebook#2939

@​public

Reviewed By: @vjeux

Differential Revision: D2467324

jestSupport/preprocessor.js

@@ -14,6 +14,16 @@ const transformer = require('../packager/transformer.js');
 
 module.exports = {
   process(src, file) {
+    // Don't transform node_modules, except react-tools which includes the
+    // untransformed copy of React
+    if (
+      file.match(/node_modules\/(?!react-tools\/)/) ||
+      // (TODO: balpert, cpojer): Remove this once react is updated to 0.14
+      file.endsWith('performanceNow.js')
+    ) {
+      return src;
+    }
+
     return transformer.transform(src, file).code;
   },