[V8] Unify get function name for debugging purpose

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 66c3043b4aa75f4dda797c749195d22d01ed3511..a5d5495d083f38966e3e47c81850b981f47867bd 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -3269,6 +3269,12 @@ class V8_EXPORT Function : public Object {
   Local<Value> GetInferredName() const;
 
   /**
+   * displayName if it is set, otherwise name if it is configured, otherwise
+   * function name, otherwise inferred name.
+   */
+  Local<Value> GetDebugName() const;
+
+  /**
    * User-defined name assigned to the "displayName" property of this function.
    * Used to facilitate debugging and profiling of JavaScript code.
    */