[TurboFan] Fix failure in JSCallReducerTest

JSBoundFunctionRef::serialized() and JSFunctionRef::serialized() should
tolerate being called when the heap broker is disabled, because these
methods are now called in the JSCallReducer (in order to log whether
information was missing at serialization time).

Bug: v8:7790
Change-Id: Iac8e68178422bd9bb4ebe2acb412ff42ac87cf4a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1733075Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63045}

src/compiler/js-heap-broker.cc

@@ -3656,12 +3656,12 @@ void JSFunctionRef::Serialize() {
 }
 
 bool JSBoundFunctionRef::serialized() const {
-  CHECK_NE(broker()->mode(), JSHeapBroker::kDisabled);
+  if (broker()->mode() == JSHeapBroker::kDisabled) return true;
   return data()->AsJSBoundFunction()->serialized();
 }
 
 bool JSFunctionRef::serialized() const {
-  CHECK_NE(broker()->mode(), JSHeapBroker::kDisabled);
+  if (broker()->mode() == JSHeapBroker::kDisabled) return true;
   return data()->AsJSFunction()->serialized();
 }