Move the canonical empty context to the VM isolate.

runtime/vm/clustered_snapshot.cc

Index: runtime/vm/clustered_snapshot.cc
diff --git a/runtime/vm/clustered_snapshot.cc b/runtime/vm/clustered_snapshot.cc
index 6faedb87a23dae15fbf864d935d0e3cc658d68dc..7676242958a32f32d01a704702d6217bd6370ddb 100644
--- a/runtime/vm/clustered_snapshot.cc
+++ b/runtime/vm/clustered_snapshot.cc
@@ -4760,6 +4760,7 @@ void Serializer::AddVMIsolateBaseObjects() {
   AddBaseObject(Bool::False().raw());
   AddBaseObject(Object::extractor_parameter_types().raw());
   AddBaseObject(Object::extractor_parameter_names().raw());
+  AddBaseObject(Object::empty_context().raw());
   AddBaseObject(Object::empty_context_scope().raw());
   AddBaseObject(Object::empty_descriptors().raw());
   AddBaseObject(Object::empty_var_descriptors().raw());
@@ -5158,6 +5159,7 @@ void Deserializer::AddVMIsolateBaseObjects() {
   AddBaseObject(Bool::False().raw());
   AddBaseObject(Object::extractor_parameter_types().raw());
   AddBaseObject(Object::extractor_parameter_names().raw());
+  AddBaseObject(Object::empty_context().raw());
   AddBaseObject(Object::empty_context_scope().raw());
   AddBaseObject(Object::empty_descriptors().raw());
   AddBaseObject(Object::empty_var_descriptors().raw());