nr rlc: fix standalone tests

./run_tests.sh was not functional anymore because of the introduction
of AssertFatal() in nr_rlc_entity.c

Including the .h and providing exit_function() solves the problem.

openair2/LAYER2/nr_rlc/nr_rlc_entity.c

@@ -30,6 +30,7 @@
 #include "LOG/log.h"
 
 #include "common/utils/time_stat.h"
+#include "common/utils/assertions.h"
 
 static void nr_rlc_entity_get_stats(
     nr_rlc_entity_t *entity,

openair2/LAYER2/nr_rlc/tests/test.c

@@ -207,6 +207,15 @@ void max_retx_reached_ue(void *max_retx_reached_data,
   exit(1);
 }
 
+#ifdef _STANDALONE_TESTING_
+
+void exit_function(const char *file, const char *function, const int line, const char *s, const int assert)
+{
+  exit(1);
+}
+
+#endif
+
 int test_main(void)
 {
   nr_rlc_entity_t *gnb = NULL;