Revert of Introduce v8::MicrotasksScope.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index a784619d6fb3a4be19baff4da3389ed40fe9caff..a6f73128882581fcda0dc2ee417996ac40cb9072 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2710,11 +2710,7 @@
 
 void Isolate::FireCallCompletedCallback() {
   bool has_call_completed_callbacks = !call_completed_callbacks_.is_empty();
-  bool run_microtasks =
-      pending_microtask_count() &&
-      !handle_scope_implementer()->HasMicrotasksSuppressions() &&
-      handle_scope_implementer()->microtasks_policy() ==
-          v8::MicrotasksPolicy::kAuto;
+  bool run_microtasks = autorun_microtasks() && pending_microtask_count();
   if (!has_call_completed_callbacks && !run_microtasks) return;
 
   if (!handle_scope_implementer()->CallDepthIsZero()) return;