Add multithreading test for SamplingCircularQueue, fix implementation.

src/cpu-profiler.h

Index: src/cpu-profiler.h
diff --git a/src/cpu-profiler.h b/src/cpu-profiler.h
index ccfac5c5c7e5601115e44ffe83dab31c9a2670b5..8a7d2fdd31893a931fea71f8f0e4ea4bde1ab6fc 100644
--- a/src/cpu-profiler.h
+++ b/src/cpu-profiler.h
@@ -154,14 +154,11 @@ class ProfilerEventsProcessor : public Thread {
   void FunctionMoveEvent(Address from, Address to);
   void FunctionDeleteEvent(Address from);
 
-  // Tick sampler registration. Called by sampler thread or signal handler.
-  inline void SetUpSamplesProducer() { ticks_buffer_.SetUpProducer(); }
   // Tick sample events are filled directly in the buffer of the circular
   // queue (because the structure is of fixed width, but usually not all
   // stack frame entries are filled.) This method returns a pointer to the
   // next record of the buffer.
   INLINE(TickSample* TickSampleEvent());
-  inline void TearDownSamplesProducer() { ticks_buffer_.TearDownProducer(); }
 
  private:
   union CodeEventsContainer {