Remove call to stopLoading when loading Distilled version.

Stop loading destroys the pending entry which leads to a crash in release.
Remove the call to stop.

BUG=679721

Review-Url: https://codereview.chromium.org/2623583005
Cr-Commit-Position: refs/heads/master@{#442856}

ios/chrome/browser/reading_list/reading_list_web_state_observer.mm

@@ -271,7 +271,6 @@ void ReadingListWebStateObserver::LoadOfflineReadingListEntry() {
   web::NavigationManager* manager = web_state()->GetNavigationManager();
   web::NavigationItem* item = manager->GetPendingItem();
   if (item) {
-    web_state()->Stop();
     web::WebState::OpenURLParams params(url, item->GetReferrer(),
                                         WindowOpenDisposition::CURRENT_TAB,
                                         item->GetTransitionType(), NO);