use TEST_EXIT_CODE instead of 0

tests/test_abort_c.c

@@ -110,5 +110,5 @@ static void custom_error_handler(
   // MPI_Abort may yield non-zero error codes of mpirun hence we
   // terminate the programm gracefully
   MPI_Finalize();
-  exit(0);
+  exit(TEST_EXIT_CODE);
 }