Use this rather than global in prelude

Summary: in new-style builds, the prelude is not wrapped into an IIFE, so `global` is not available. Since the bundle as a whole is not running in strict mode, we can access the global object with `this`.

Reviewed By: jeanlauliac

Differential Revision: D5051731

fbshipit-source-id: 4003b5e57ba8626e38e68e92d5778c2c59ca69a5

packager/src/ModuleGraph/ModuleGraph.js

@@ -97,6 +97,6 @@ function* concat<T>(...iterables: Array<Iterable<T>>): Iterable<T> {
 function prelude(optimize) {
   return virtualModule(
     `var __DEV__=${String(!optimize)},` +
-    '__BUNDLE_START_TIME__=global.nativePerformanceNow?global.nativePerformanceNow():Date.now();'
+    '__BUNDLE_START_TIME__=this.nativePerformanceNow?nativePerformanceNow():Date.now();'
   );
 }