return packager URL instead of proxy URL when debugging

Summary:
JS relies on the URL returned by SourceCodeModule to load packager assets. Because we currently return localhost when debugging (because that's the URL Chrome uses), assets don't load when debugging. This makes it so SourceCodeModule still returns the package URL relative to the emulator / device even when debugging.

public

Reviewed By: astreet

Differential Revision: D2759710

fb-gh-sync-id: bab6a88ef044b8b4d971381e3b23c59fa9aa2ed0

ReactAndroid/src/main/java/com/facebook/react/ReactInstanceManagerImpl.java

@@ -507,7 +507,8 @@ import com.facebook.systrace.Systrace;
     recreateReactContextInBackground(
         new ProxyJavaScriptExecutor(jsExecutor),
         JSBundleLoader.createRemoteDebuggerBundleLoader(
-            mDevSupportManager.getJSBundleURLForRemoteDebugging()));
+            mDevSupportManager.getJSBundleURLForRemoteDebugging(),
+            mDevSupportManager.getSourceUrl()));
   }
 
   private void onJSBundleLoadedFromServer() {