patch 8.0.0699: checksum tests are not actually run

Problem:    Checksum tests are not actually run.
Solution:   Add the tests to the list. (Dominique Pelle, closes #1819)
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index fec2271..8e245ed 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -44,6 +44,7 @@
 source test_searchpos.vim
 source test_set.vim
 source test_sort.vim
+source test_sha256.vim
 source test_statusline.vim
 source test_syn_attr.vim
 source test_tabline.vim