Reland "Handlify GetProperty."

src/handles.cc

Index: src/handles.cc
diff --git a/src/handles.cc b/src/handles.cc
index a58707e0761d95510046627b7faadb6a5c3260a8..af1ffab59c3b2928da8ea35ebc90d24774dda3ca 100644
--- a/src/handles.cc
+++ b/src/handles.cc
@@ -394,8 +394,8 @@ Handle<Object> GetScriptNameOrSourceURL(Handle<Script> script) {
       isolate->factory()->InternalizeOneByteString(
           STATIC_ASCII_VECTOR("nameOrSourceURL"));
   Handle<JSValue> script_wrapper = GetScriptWrapper(script);
-  Handle<Object> property =
-      Object::GetProperty(script_wrapper, name_or_source_url_key);
+  Handle<Object> property = Object::GetProperty(
+      script_wrapper, name_or_source_url_key).ToHandleChecked();
   ASSERT(property->IsJSFunction());
   Handle<JSFunction> method = Handle<JSFunction>::cast(property);
   Handle<Object> result;