8254264: Remove redundant cross_modify_fence()

Reviewed-by: rehn, dholmes, dcubed

Author: pchilano

src/hotspot/share/runtime/interfaceSupport.inline.hpp

@@ -231,7 +231,6 @@ class ThreadBlockInVM : public ThreadStateTransition {
   }
   ~ThreadBlockInVM() {
     trans(_thread_blocked, _thread_in_vm);
-    OrderAccess::cross_modify_fence();
     // We don't need to clear_walkable because it will happen automagically when we return to java
   }
 };
@@ -281,7 +280,6 @@ class ThreadBlockInVMWithDeadlockCheck : public ThreadStateTransition {
     }
 
     _thread->set_thread_state(_thread_in_vm);
-    OrderAccess::cross_modify_fence();
   }
 };
 

src/hotspot/share/runtime/thread.cpp

@@ -2605,9 +2605,6 @@ void JavaThread::java_suspend_self_with_safepoint_check() {
     set_thread_state_fence(state);
   } while (is_external_suspend());
 
-  // Since we are not using a regular thread-state transition helper here,
-  // we must manually emit the instruction barrier after leaving a safe state.
-  OrderAccess::cross_modify_fence();
   if (state != _thread_in_native) {
     SafepointMechanism::process_if_requested(this);
   }