[debugger] simplify step over recursive function call.

src/debug/debug.h

Index: src/debug/debug.h
diff --git a/src/debug/debug.h b/src/debug/debug.h
index 32f70a42e6aadb1d4fd9823b2380a9fde9742d58..955cd57dcc0f6fc538c8d765c8caa3cc4cca7688 100644
--- a/src/debug/debug.h
+++ b/src/debug/debug.h
@@ -630,9 +630,6 @@ class Debug {
     // Frame pointer from last step next or step frame action.
     Address last_fp_;
 
-    // Number of queued steps left to perform before debug event.
-    int queued_step_count_;
-
     // Frame pointer for the frame where debugger should be called when current
     // step out action is completed.
     Address step_out_fp_;