Whenever possible use length passed to the List constructor for bounds checks instead of loading it…

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
diff --git a/runtime/vm/flow_graph_builder.cc b/runtime/vm/flow_graph_builder.cc
index 927ee050ef0c1d2a26ff190836777ab951b7e3fa..4a66bdd661fe7d4217cb7f7cb0859e13a70fcb3d 100644
--- a/runtime/vm/flow_graph_builder.cc
+++ b/runtime/vm/flow_graph_builder.cc
@@ -1687,7 +1687,9 @@ void EffectGraphVisitor::VisitConstructorCallNode(ConstructorCallNode* node) {
                             node->arguments()->names(),
                             arguments);
     // List factories return kArrayCid or kGrowableObjectArrayCid.
-    call->set_result_cid(GetResultCidOfConstructor(node));
+    const intptr_t result_cid = GetResultCidOfConstructor(node);
+    call->set_result_cid(result_cid);
+    call->set_is_known_constructor(result_cid != kDynamicCid);
     ReturnDefinition(call);
     return;
   }