Mark lazily-patched native calls correctly as patchable.

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
diff --git a/runtime/vm/flow_graph_compiler_x64.cc b/runtime/vm/flow_graph_compiler_x64.cc
index 8a8b24f7b3d148a40d0e955e3cc55127a93f3ecf..a4b1288b0defc0d1e2d532d5ba67cabc6dfc182c 100644
--- a/runtime/vm/flow_graph_compiler_x64.cc
+++ b/runtime/vm/flow_graph_compiler_x64.cc
@@ -1094,6 +1094,16 @@ void FlowGraphCompiler::GenerateCall(TokenPosition token_pos,
 }
 
 
+void FlowGraphCompiler::GeneratePatchableCall(TokenPosition token_pos,
+                                              const StubEntry& stub_entry,
+                                              RawPcDescriptors::Kind kind,
+                                              LocationSummary* locs) {
+  __ CallPatchable(stub_entry);
+  AddCurrentDescriptor(kind, Thread::kNoDeoptId, token_pos);
+  RecordSafepoint(locs);
+}
+
+
 void FlowGraphCompiler::GenerateDartCall(intptr_t deopt_id,
                                          TokenPosition token_pos,
                                          const StubEntry& stub_entry,