Debug/getStepIntoPositions, fix case for no debug-info

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index a1c0d750c4a0ec3ec81d245e8c8bcae90d5740d0..960aa4586416d6e72256c710f90e059b5cb00b4c 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -12014,8 +12014,14 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetStepInPositions) {
   JavaScriptFrameIterator frame_it(isolate, id);
   JavaScriptFrame* frame = frame_it.frame();
 
+  Handle<JSFunction> fun =
+      Handle<JSFunction>(frame->function());
   Handle<SharedFunctionInfo> shared =
-      Handle<SharedFunctionInfo>(frame->function()->shared());
+      Handle<SharedFunctionInfo>(fun->shared());
+  bool has_info = isolate->debug()->EnsureDebugInfo(shared, fun);
+  if (!has_info) {
+    return isolate->heap()->undefined_value();
+  }
   Handle<DebugInfo> debug_info = Debug::GetDebugInfo(shared);
 
   int len = 0;