utils/cache_gc/kr_cache_gc.c: replace asserts

utils/cache_gc/kr_cache_gc.c

@@ -151,7 +151,8 @@ struct kr_cache_gc_state {
 
 void kr_cache_gc_free_state(kr_cache_gc_state_t **state)
 {
-	assert(state);
+	if (!kr_assume(state))
+		return;
 	if (!*state) { // not open
 		return;
 	}
@@ -164,7 +165,8 @@ int kr_cache_gc(kr_cache_gc_cfg_t *cfg, kr_cache_gc_state_t **state)
 {
 	// The whole function works in four "big phases":
 	//// 1. find out whether we should even do analysis and deletion.
-	assert(cfg && state);
+	if (!kr_assume(cfg && state))
+		return KNOT_EINVAL;
 	int ret;
 	// Ensure that we have open and "healthy" cache.
 	if (!*state) {