Parser: fixed njs_queue_remove() macro usage.

The issue caused segfault when NJS_DEBUG is defined.

The issue was introduced in 86f55a7dc4a4.
diff --git a/src/njs_parser.c b/src/njs_parser.c
index 5b80619..879459e 100644
--- a/src/njs_parser.c
+++ b/src/njs_parser.c
@@ -480,13 +480,15 @@
 njs_inline njs_int_t
 njs_parser_reject(njs_parser_t *parser)
 {
+    njs_queue_link_t          *link;
     njs_parser_stack_entry_t  *entry;
 
     while (!njs_queue_is_empty(&parser->stack)) {
         entry = njs_queue_link_data(njs_queue_first(&parser->stack),
                                     njs_parser_stack_entry_t, link);
 
-        njs_queue_remove(njs_queue_first(&parser->stack));
+        link = njs_queue_first(&parser->stack);
+        njs_queue_remove(link);
 
         if (!entry->optional) {
             njs_parser_next(parser, entry->state);
diff --git a/src/njs_parser.h b/src/njs_parser.h
index 72e75f8..62c6e5f 100644
--- a/src/njs_parser.h
+++ b/src/njs_parser.h
@@ -280,13 +280,14 @@
 njs_inline njs_int_t
 njs_parser_stack_pop(njs_parser_t *parser)
 {
+    njs_queue_link_t          *link;
     njs_parser_stack_entry_t  *entry;
 
-
     entry = njs_queue_link_data(njs_queue_first(&parser->stack),
                                 njs_parser_stack_entry_t, link);
 
-    njs_queue_remove(njs_queue_first(&parser->stack));
+    link = njs_queue_first(&parser->stack);
+    njs_queue_remove(link);
 
 #ifdef NJS_PARSER_DEBUG
     njs_printf("  stack_pop(%d)\n",