patch 8.0.0268: may get ml_get error when :luado deletes lines

Problem:    May get ml_get error when :luado deletes lines or switches to
            another buffer. (Nikolai Pavlov, issue #1421)
Solution:   Check the buffer and line every time.
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index c01634c..bb646ee 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -164,6 +164,7 @@
 	    test_job_fails.res \
 	    test_json.res \
 	    test_langmap.res \
+	    test_lua.res \
 	    test_man.res \
 	    test_marks.res \
 	    test_matchadd_conceal.res \
@@ -172,8 +173,8 @@
 	    test_nested_function.res \
 	    test_netbeans.res \
 	    test_normal.res \
-	    test_paste.res \
 	    test_packadd.res \
+	    test_paste.res \
 	    test_perl.res \
 	    test_profile.res \
 	    test_python2.res \