patch 8.0.1039: cannot change a line in not current buffer

Problem:    Cannot change a line in a buffer other than the current one.
Solution:   Add setbufline(). (Yasuhiro Matsumoto, Ozaki Kiichi, closes #1953)
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index e83256a..189cd82 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -3,6 +3,7 @@
 
 set belloff=all
 source test_assign.vim
+source test_bufline.vim
 source test_cd.vim
 source test_changedtick.vim
 source test_cursor_func.vim