[bugfix] Ensure that ContextParam#sequence is null'ed so that memory is not leaked if the query is cached for reuse

Author: adamretter

exist-core/src/main/java/org/exist/xquery/ArrowOperator.java

@@ -252,5 +252,11 @@ public int returnsType() {
         @Override
         public void dump(final ExpressionDumper dumper) {
         }
+
+        @Override
+        public void resetState(final boolean postOptimization) {
+            super.resetState(postOptimization);
+            this.sequence = null;
+        }
     }
 }