Improve error message when attempting to evaluate against a VM-internal object (e.g., a Megamorphic…

runtime/vm/service.cc

Index: runtime/vm/service.cc
diff --git a/runtime/vm/service.cc b/runtime/vm/service.cc
index d346361653ed37a201a858b059617c7591e9aa90..499964f80262c87df966af803468bafb989758d3 100644
--- a/runtime/vm/service.cc
+++ b/runtime/vm/service.cc
@@ -2159,8 +2159,7 @@ static bool Evaluate(Thread* thread, JSONStream* js) {
   }
   js->PrintError(kInvalidParams,
                  "%s: invalid 'targetId' parameter: "
-                 "id '%s' does not correspond to a "
-                 "library, class, or instance", js->method(), target_id);
+                 "Cannot evaluate against a VM-internal object", js->method());
   return true;
 }