patch 9.1.0546: vim-tiny fails on CTRL-X/CTRL-A

Problem:  vim-tiny fails on CTRL-X/CTRL-A
          (Rob Foehl, after 9.1.0172)
Solution: Move #ifdefs, so that after changing the line in del_bytes,
          the cached textlen value is invalidated

closes: #15178

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test28.ok b/src/testdir/test28.ok
new file mode 100644
index 0000000..085c133
--- /dev/null
+++ b/src/testdir/test28.ok
@@ -0,0 +1,3 @@
+12353
+
+12353