[Intl] Remove redundant call

Bug: v8:7684
Change-Id: If74e2b6d1ff7d11f3133ff74847d23b171b05f0a
Reviewed-on: https://chromium-review.googlesource.com/c/1459744Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59477}

src/objects/intl-objects.cc

@@ -799,7 +799,7 @@ Maybe<std::string> Intl::CanonicalizeLanguageTag(Isolate* isolate,
         Nothing<std::string>());
   }
 
-  return Intl::ToLanguageTag(icu_locale);
+  return maybe_to_language_tag;
 }
 
 Maybe<std::vector<std::string>> Intl::CanonicalizeLocaleList(