Assume that ReportFailedAccessCheck always schedules an exception.

src/runtime/runtime-classes.cc

Index: src/runtime/runtime-classes.cc
diff --git a/src/runtime/runtime-classes.cc b/src/runtime/runtime-classes.cc
index 53583086121b130c0211d67d680188821b4da90a..4c0627e168389e5ce834449e7bfbf1cf2881b05d 100644
--- a/src/runtime/runtime-classes.cc
+++ b/src/runtime/runtime-classes.cc
@@ -272,6 +272,7 @@ static MaybeHandle<Object> LoadFromSuper(Isolate* isolate,
       !isolate->MayAccess(handle(isolate->context()), home_object)) {
     isolate->ReportFailedAccessCheck(home_object);
     RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
+    UNREACHABLE();
   }
 
   PrototypeIterator iter(isolate, home_object);
@@ -297,6 +298,7 @@ static MaybeHandle<Object> LoadElementFromSuper(Isolate* isolate,
       !isolate->MayAccess(handle(isolate->context()), home_object)) {
     isolate->ReportFailedAccessCheck(home_object);
     RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
+    UNREACHABLE();
   }
 
   PrototypeIterator iter(isolate, home_object);
@@ -374,6 +376,7 @@ static Object* StoreToSuper(Isolate* isolate, Handle<JSObject> home_object,
       !isolate->MayAccess(handle(isolate->context()), home_object)) {
     isolate->ReportFailedAccessCheck(home_object);
     RETURN_FAILURE_IF_SCHEDULED_EXCEPTION(isolate);
+    UNREACHABLE();
   }
 
   PrototypeIterator iter(isolate, home_object);
@@ -399,6 +402,7 @@ static Object* StoreElementToSuper(Isolate* isolate,
       !isolate->MayAccess(handle(isolate->context()), home_object)) {
     isolate->ReportFailedAccessCheck(home_object);
     RETURN_FAILURE_IF_SCHEDULED_EXCEPTION(isolate);
+    UNREACHABLE();
   }
 
   PrototypeIterator iter(isolate, home_object);