[inspector] migrate stepping related methods to debug-interface

src/debug/debug.h

Index: src/debug/debug.h
diff --git a/src/debug/debug.h b/src/debug/debug.h
index 4d591d053134560189e9f7fa4e16dc324771ed58..30cbe77f8b37aa71895d49b54c60c29fe29cd88c 100644
--- a/src/debug/debug.h
+++ b/src/debug/debug.h
@@ -501,8 +501,11 @@ class Debug {
   void Iterate(ObjectVisitor* v);
 
   bool CheckExecutionState(int id) {
-    return is_active() && !debug_context().is_null() && break_id() != 0 &&
-           break_id() == id;
+    return CheckExecutionState() && break_id() == id;
+  }
+
+  bool CheckExecutionState() {
+    return is_active() && !debug_context().is_null() && break_id() != 0;
   }
 
   // Flags and states.