[inspector] async stacks for Promise.then calls...

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index e5f1766a831f47a52197e459b4858518dc6089ca..d4fbb88000e4e5f4af6fb58af46ec6224ac7f150 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -407,7 +407,6 @@ typedef List<HeapObject*> DebugObjectCache;
   V(v8::DeserializeInternalFieldsCallback,                                    \
     deserialize_internal_fields_callback, nullptr)                            \
   V(int, pending_microtask_count, 0)                                          \
-  V(int, debug_microtask_count, 0)                                            \
   V(HStatistics*, hstatistics, nullptr)                                       \
   V(CompilationStatistics*, turbo_statistics, nullptr)                        \
   V(HTracer*, htracer, nullptr)                                               \
@@ -1108,7 +1107,6 @@ class Isolate {
   void EnqueueMicrotask(Handle<Object> microtask);
   void RunMicrotasks();
   bool IsRunningMicrotasks() const { return is_running_microtasks_; }
-  int GetNextDebugMicrotaskId() { return debug_microtask_count_++; }
 
   Handle<Symbol> SymbolFor(Heap::RootListIndex dictionary_index,
                            Handle<String> name, bool private_symbol);