7034957: acquiring lock CodeCache_lock/1 out of order with lock tty_lock/0 -- possible deadlock

Reviewed-by: iveresov

src/share/vm/code/codeCache.cpp

@@ -971,6 +971,8 @@ size_t CodeCache::largest_free_block() {
   if (CodeCache_lock->owned_by_self()) {
     return _heap->largest_free_block();
   } else {
+    // Avoid lock ordering problems with ttyLock.
+    ttyUnlocker ttyul;
     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
     return _heap->largest_free_block();
   }