[strong] Refactor ObjectStrength into a replacement for strong boolean args

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index efa0e28ba06529c788ef3dc6e19e37494b897dd5..e8081f103de0bfe649f73e03457c413e0ede2822 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2373,11 +2373,11 @@ CodeTracer* Isolate::GetCodeTracer() {
 }
 
 
-Map* Isolate::get_initial_js_array_map(ElementsKind kind,
-                                       ObjectStrength strength) {
+Map* Isolate::get_initial_js_array_map(ElementsKind kind, Strength strength) {
   Context* native_context = context()->native_context();
-  Object* maybe_map_array = strength ? native_context->js_array_strong_maps()
-                                     : native_context->js_array_maps();
+  Object* maybe_map_array = is_strong(strength)
+                                ? native_context->js_array_strong_maps()
+                                : native_context->js_array_maps();
   if (!maybe_map_array->IsUndefined()) {
     Object* maybe_transitioned_map =
         FixedArray::cast(maybe_map_array)->get(kind);