The new oldtest directory is in test/old/testdir. The reason for this is
that many tests have hardcoded the parent directory name to be
'testdir'.

Problem:    assert_fails() checks the last error message.
Solution:   Check the first error, it is more relevant.  Fix all the tests
            that rely on the old behavior.

https://github.com/vim/vim/commit/9b7bf9e98f06ece595fed7a3ff53ecce89797a53

Skip test_listener.vim, test_textprop.vim, test_viminfo.vim.
Skip test_python2.vim: affected line fails and hasn't been ported.
Skip test_python3.vim: affected lines fail and haven't been ported.
Skip CHECK_LIST_MATERIALIZE.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

Problem:    Insufficient testing for invalid function arguments.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#5988)

https://github.com/vim/vim/commit/99fa721944dda9d07c53c907c33466728df5c271

Omit test_listener.vim: changed again in patch 8.2.1183.
Omit test_textprop.vim: changed again in patch 8.2.1183.
Cherry-pick quickfix feature checks from patch 8.1.2373.
Omit Test_saveas() change: duplicate and removed in patch 8.2.0866.

Co-authored-by: Marco Lehmann <m99@posteo.de>

Problem:    <amatch> of MenuPopup event is expanded like a file name.
Solution:   Do not expand <amatch> for MenuPopup. (closes vim/vim#11328)
https://github.com/vim/vim/commit/c601d988b6b1a672f71e3d61f4aaa4f7742a3a21

Problem:    "delmenu" does not remove autocmmands. Running menu test function
            alone fails.
Solution:   Delete autocommands Make sure there is at least one menu.
            (closes vim/vim#10848)
https://github.com/vim/vim/commit/206fce307b265f7f6c6290b623a80c1d846dd131

Problem:    Going past the end of a menu item with only modifier.
Solution:   Check for NUL.
https://github.com/vim/vim/commit/083692d598139228e101b8c521aaef7bcf256e9a

Problem:    New buffers are not added to the Buffers menu.
Solution:   Turn number into string. (Yee Cheng Chin, closes vim/vim#5864)
https://github.com/vim/vim/commit/5908fdf72fa1995735e38c46f254ddde81a87c1f

Problem:    Buffer menu does not handle special buffers properly.
Solution:   Keep a dictionary with buffer names to reliably keep track of
            entries.
            Also trigger BufFilePre and BufFilePost for command-line and
            terminal buffers when the name changes.
https://github.com/vim/vim/commit/5e94a29ebbde10dd973d58f1adba9a2fc83877d1

Problem:    Vim9: need more tests for empty string arguments.
Solution:   Add more tests.  Also use empty argument with menu_info() to get
            the top-level menu names. (Yegappan Lakshmanan, closes vim/vim#8925)
https://github.com/vim/vim/commit/51491adfa86fd66a857cd7ec50d0b57dbdf3da59