Add Genericity enum in VM to distinguish how a type is uninstantiated.

runtime/vm/flow_graph_inliner.cc

Index: runtime/vm/flow_graph_inliner.cc
diff --git a/runtime/vm/flow_graph_inliner.cc b/runtime/vm/flow_graph_inliner.cc
index 88f3575ff58b73d8ba031aebe22e6822831655a1..1d3937704a34d910e05de19ccb421b8a24a49274 100644
--- a/runtime/vm/flow_graph_inliner.cc
+++ b/runtime/vm/flow_graph_inliner.cc
@@ -2423,6 +2423,7 @@ static bool InlineSetIndexed(FlowGraph* flow_graph,
     }
     AssertAssignableInstr* assert_value = new (Z) AssertAssignableInstr(
         token_pos, new (Z) Value(stored_value), new (Z) Value(type_args),
+        NULL,  // TODO(regis): Pass null value for function type arguments.
         value_type, Symbols::Value(), call->deopt_id());
     cursor = flow_graph->AppendTo(cursor, assert_value, call->env(),
                                   FlowGraph::kValue);