Revert^4 "Implement LockSupport.park with a futex"

This reverts commit 13f4d9631db981ae5008073db4df9c6a934fc9f3.

Reason for revert: Fixing ThreadStress timeouts.

Change-Id: I9f8c3f56eccfadc3751049731e8d427873cc7841
diff --git a/runtime/thread.h b/runtime/thread.h
index 941867c..b304cef 100644
--- a/runtime/thread.h
+++ b/runtime/thread.h
@@ -581,6 +581,11 @@
     return poison_object_cookie_;
   }
 
+  // Parking for 0ns of relative time means an untimed park, negative (though
+  // should be handled in java code) returns immediately
+  void Park(bool is_absolute, int64_t time) REQUIRES_SHARED(Locks::mutator_lock_);
+  void Unpark();
+
  private:
   void NotifyLocked(Thread* self) REQUIRES(wait_mutex_);
 
@@ -1543,6 +1548,8 @@
     // Thread "interrupted" status; stays raised until queried or thrown.
     Atomic<bool32_t> interrupted;
 
+    AtomicInteger park_state_;
+
     // True if the thread is allowed to access a weak ref (Reference::GetReferent() and system
     // weaks) and to potentially mark an object alive/gray. This is used for concurrent reference
     // processing of the CC collector only. This is thread local so that we can enable/disable weak