Fix bug in field type tracking and polymorphic inlining.

runtime/vm/flow_graph_inliner.cc

Index: runtime/vm/flow_graph_inliner.cc
===================================================================
--- runtime/vm/flow_graph_inliner.cc	(revision 27611)
+++ runtime/vm/flow_graph_inliner.cc	(working copy)
@@ -546,6 +546,7 @@
       FlowGraphBuilder builder(parsed_function,
                                ic_data_array,
                                exit_collector,
+                               guarded_fields_,
                                Isolate::kNoDeoptId);
       builder.SetInitialBlockId(caller_graph_->max_block_id());
       FlowGraph* callee_graph;
@@ -606,7 +607,7 @@
                          &CompilerStats::graphinliner_opt_timer,
                          isolate);
         // TODO(zerny): Do more optimization passes on the callee graph.
-        FlowGraphOptimizer optimizer(callee_graph, guarded_fields_);
+        FlowGraphOptimizer optimizer(callee_graph);
         optimizer.ApplyICData();
         DEBUG_ASSERT(callee_graph->VerifyUseLists());
       }