Always update scheduled thread id

runtime/vm/profiler.cc

Index: runtime/vm/profiler.cc
diff --git a/runtime/vm/profiler.cc b/runtime/vm/profiler.cc
index a6e53a7fb64832d7a1e2410b2c0a790f9402de8b..6ebe829103c80d7e52d29bf9af09abee0b4085bb 100644
--- a/runtime/vm/profiler.cc
+++ b/runtime/vm/profiler.cc
@@ -171,11 +171,6 @@ void ProfilerManager::ShutdownIsolateForProfiling(Isolate* isolate) {
 
 void ProfilerManager::ScheduleIsolateHelper(Isolate* isolate) {
   ScopedMonitor lock(monitor_);
-  intptr_t i = FindIsolate(isolate);
-  if (i >= 0) {
-    // Already scheduled.
-    return;
-  }
   {
     ScopedMutex profiler_data_lock(isolate->profiler_data_mutex());
     IsolateProfilerData* profiler_data = isolate->profiler_data();
@@ -185,6 +180,11 @@ void ProfilerManager::ScheduleIsolateHelper(Isolate* isolate) {
     profiler_data->Scheduled(OS::GetCurrentTimeMicros(),
                              Thread::GetCurrentThreadId());
   }
+  intptr_t i = FindIsolate(isolate);
+  if (i >= 0) {
+    // Already scheduled.
+    return;
+  }
   AddIsolate(isolate);
   lock.Notify();
 }