8043158: Crash in CodeSweeperSweepNoFlushTest in CompileQueue::free_all()

Summary: Acquire lock before calling notify()
Reviewed-by: twisti, thartmann

src/share/vm/compiler/compileBroker.cpp

@@ -678,8 +678,11 @@ void CompileQueue::free_all() {
   while (next != NULL) {
     CompileTask* current = next;
     next = current->next();
-    // Wake up thread that blocks on the compile task.
-    current->lock()->notify();
+    {
+      // Wake up thread that blocks on the compile task.
+      MutexLocker ct_lock(current->lock());
+      current->lock()->notify();
+    }
     // Put the task back on the freelist.
     CompileTask::free(current);
   }