Allocate generic types in new-space before canonicalizing.

runtime/vm/flow_graph_type_propagator.cc

Index: runtime/vm/flow_graph_type_propagator.cc
diff --git a/runtime/vm/flow_graph_type_propagator.cc b/runtime/vm/flow_graph_type_propagator.cc
index bc4a844d32c2e9f75d3f0dbd9f6d1f29477a692c..9f96d7d7ca2beab4cbe7d49a62f7c7c6a9e9eef4 100644
--- a/runtime/vm/flow_graph_type_propagator.cc
+++ b/runtime/vm/flow_graph_type_propagator.cc
@@ -804,8 +804,11 @@ CompileType ConstantInstr::ComputeType() const {
   }
 
   if (value().IsInstance()) {
+    // Allocate in old-space since this may be invoked from the
+    // background compiler.
     return CompileType::Create(
-        cid, AbstractType::ZoneHandle(Instance::Cast(value()).GetType()));
+        cid,
+        AbstractType::ZoneHandle(Instance::Cast(value()).GetType(Heap::kOld)));
   } else {
     // Type info for non-instance objects.
     return CompileType::FromCid(cid);