microtask queue: Fix trace event ordering.

The previous ordering caused a SCOPED event to end after its parent
event, which isn't really supported in the trace format.

Change-Id: I2ddaa12596604499366854231506c889d910f951
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1741926Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Auto-Submit: Eric Seckler <eseckler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63118}

src/execution/microtask-queue.cc

@@ -159,10 +159,13 @@ int MicrotaskQueue::RunMicrotasks(Isolate* isolate) {
     HandleScopeImplementer::EnteredContextRewindScope rewind_scope(
         isolate->handle_scope_implementer());
     TRACE_EVENT_BEGIN0("v8.execute", "RunMicrotasks");
-    TRACE_EVENT_CALL_STATS_SCOPED(isolate, "v8", "V8.RunMicrotasks");
-    maybe_result = Execution::TryRunMicrotasks(isolate, this, &maybe_exception);
-    processed_microtask_count =
-        static_cast<int>(finished_microtask_count_ - base_count);
+    {
+      TRACE_EVENT_CALL_STATS_SCOPED(isolate, "v8", "V8.RunMicrotasks");
+      maybe_result = Execution::TryRunMicrotasks(isolate, this,
+                                                 &maybe_exception);
+      processed_microtask_count =
+          static_cast<int>(finished_microtask_count_ - base_count);
+    }
     TRACE_EVENT_END1("v8.execute", "RunMicrotasks", "microtask_count",
                      processed_microtask_count);
   }