NJS: adding the missing vm destruction.

This commit fixed the njs memory leak happened in the config validation, updating and http requests.

src/nxt_js.c

@@ -46,6 +46,7 @@ nxt_js_conf_new(nxt_mp_t *mp)
 
     jcf->funcs = nxt_array_create(mp, 4, sizeof(nxt_str_t));
     if (nxt_slow_path(jcf->funcs == NULL)) {
+        njs_vm_destroy(jcf->vm);
         return NULL;
     }
 
@@ -53,6 +54,13 @@ nxt_js_conf_new(nxt_mp_t *mp)
 }
 
 
+void
+nxt_js_conf_release(nxt_js_conf_t *jcf)
+{
+    njs_vm_destroy(jcf->vm);
+}
+
+
 void
 nxt_js_set_proto(nxt_js_conf_t *jcf, njs_external_t *proto, njs_uint_t n)
 {
@@ -297,3 +305,12 @@ nxt_js_call(nxt_task_t *task, nxt_js_cache_t *cache, nxt_js_t *js,
 
     return NXT_OK;
 }
+
+
+void
+nxt_js_release(nxt_js_cache_t *cache)
+{
+    if (cache->vm != NULL) {
+        njs_vm_destroy(cache->vm);
+    }
+}