diff --git a/src/handles/handles.cc b/src/handles/handles.cc
index a03a619922..85072a375a 100644
--- a/src/handles/handles.cc
+++ b/src/handles/handles.cc
@@ -43,7 +43,7 @@ bool HandleBase::IsDereferenceAllowed() const {
   }
 
   LocalHeap* local_heap = LocalHeap::Current();
-  if (V8_UNLIKELY(local_heap)) {
+  if (FLAG_local_heaps && local_heap) {
     // Local heap can't access handles when parked
     if (!local_heap->IsHandleDereferenceAllowed()) return false;
 
diff --git a/test/cctest/compiler/serializer-tester.cc b/test/cctest/compiler/serializer-tester.cc
index 404529e71e..88e0becf23 100644
--- a/test/cctest/compiler/serializer-tester.cc
+++ b/test/cctest/compiler/serializer-tester.cc
@@ -31,6 +31,7 @@ SerializerTester::SerializerTester(const char* source)
   // We need allocation of executable memory for the compilation.
   FLAG_jitless = false;
   FLAG_allow_natives_syntax = true;
+  FlagList::EnforceFlagImplications();
 
   std::string function_string = "(function() { ";
   function_string += source;