Turn the rename Save to Download experiment off

The experiment to rename "Save Image" to "Download Image" is having a negative
impact, it needs to be turned off.
This CL cleans up the code added for this experiment.

BUG=669069

Review-Url: https://codereview.chromium.org/2810233004
Cr-Commit-Position: refs/heads/master@{#465165}
diff --git a/ios/chrome/browser/ui/browser_view_controller.mm b/ios/chrome/browser/ui/browser_view_controller.mm
index 5bb9155b..2979eb4 100644
--- a/ios/chrome/browser/ui/browser_view_controller.mm
+++ b/ios/chrome/browser/ui/browser_view_controller.mm
@@ -2595,13 +2595,7 @@
   if (isImage) {
     web::Referrer referrer([_model currentTab].url, params.referrer_policy);
     // Save Image.
-    if (experimental_flags::IsDownloadRenamingEnabled()) {
-      title = l10n_util::GetNSStringWithFixup(
-          IDS_IOS_CONTENT_CONTEXT_DOWNLOADIMAGE);
-    } else {
-      title =
-          l10n_util::GetNSStringWithFixup(IDS_IOS_CONTENT_CONTEXT_SAVEIMAGE);
-    }
+    title = l10n_util::GetNSStringWithFixup(IDS_IOS_CONTENT_CONTEXT_SAVEIMAGE);
     action = ^{
       Record(ACTION_SAVE_IMAGE, isImage, isLink);
       [weakSelf saveImageAtURL:imageUrl referrer:referrer];