patch 8.2.1653: expand('<stack>') does not include the final line number

Problem:    Expand('<stack>') does not include the final line number.
Solution:   Add the line nuber. (closes #6927)
diff --git a/src/testing.c b/src/testing.c
index 8db7d62..8115441 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -22,7 +22,7 @@
 prepare_assert_error(garray_T *gap)
 {
     char    buf[NUMBUFLEN];
-    char_u  *sname = estack_sfile(FALSE);
+    char_u  *sname = estack_sfile(ESTACK_NONE);
 
     ga_init2(gap, 1, 100);
     if (sname != NULL)