7125594: C-heap growth issue in ThreadService::find_deadlocks_at_safepoint

Reviewed-by: sspitsyn, dcubed, mchung, dholmes
diff --git a/hotspot/src/share/vm/services/threadService.cpp b/hotspot/src/share/vm/services/threadService.cpp
index 09f09f2..5c70fe9 100644
--- a/hotspot/src/share/vm/services/threadService.cpp
+++ b/hotspot/src/share/vm/services/threadService.cpp
@@ -377,7 +377,7 @@
     }
 
   }
-
+  delete cycle;
   return deadlocks;
 }