[debugger] whitelist some builtins as side-effect free.

src/debug/debug.h

Index: src/debug/debug.h
diff --git a/src/debug/debug.h b/src/debug/debug.h
index 310b4cd6981a5dac5c33a85f8c61a7237e3228b6..b3bb3c46a64cfa2d673f69c4bac9b6dc5809aaeb 100644
--- a/src/debug/debug.h
+++ b/src/debug/debug.h
@@ -580,7 +580,9 @@ class Debug {
 
   // Check whether there are commands in the command queue.
   inline bool has_commands() const { return !command_queue_.IsEmpty(); }
-  inline bool ignore_events() const { return is_suppressed_ || !is_active_; }
+  inline bool ignore_events() const {
+    return is_suppressed_ || !is_active_ || isolate_->needs_side_effect_check();
+  }
   inline bool break_disabled() const {
     return break_disabled_ || in_debug_event_listener_;
   }