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:    deletebufline() may move marks in the wrong window.
Solution:   Find a window for the buffer being changed. (closes vim/vim#11583)

https://github.com/vim/vim/commit/228e422855d43965f2c3319ff0cdc26ea422c10f

Cherry-pick code change from patch 9.0.0961.

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

Problem:    getbufline() is inefficient for getting a single line.
Solution:   Add getbufoneline().

https://github.com/vim/vim/commit/ce30ccc06af7f2c03762e5b18dde37b26ea6ec42

Cherry-pick part of usr_41.txt from patch 8.1.1628.

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

Problem:    set/getbufline test fails without the job feature.
Solution:   Check whether the job feature is supported. (Dominique Pellé,
            closes vim/vim#7790)

https://github.com/vim/vim/commit/00385114dbd6a3d59516baa02e1ea86a1e7ee70e

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

Problem:    setline() gives an error for some types.
Solution:   Allow any type, convert each item to a string.

https://github.com/vim/vim/commit/3445320839a38b3b0c253513b125da8298ec27d6

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

Problem:    deletebufline() does not always return 1 on failure.
Solution:   Refactor the code to make it work more predictable. (closes vim/vim#11511)

https://github.com/vim/vim/commit/7af3ee2b83545169d78a28ab1cd89aff1127f8b3

Problem:    Regexp benchmark stest is old style.
Solution:   Make it a new style test.  Fix using a NULL list.  Add more tests.
            (Yegappan Lakshmanan, closes vim/vim#5963)

https://github.com/vim/vim/commit/ad48e6c1590842ab6d48e6caba3e9250734dae27

N/A patches:
vim-patch:9.0.0829: wrong counts in macro comment

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.

Problem:    Tests use hand coded feature and option checks.
Solution:   Use the commands from check.vim in more tests.

https://github.com/vim/vim/commit/8c5a278fc508da6dfe50e69b6ee734451aa4eafb

Omit Test_wincolor(): there are later patches that touch that function.
Omit test_memory_usage.vim: a Lua test is used for that file.
Cherry-pick Test_issue_3969() from patch 8.1.0969.

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

Problem:    'buftype' values not sufficiently tested.
Solution:   Add and extend tests with 'buftype' values. (closes vim/vim#10988)
https://github.com/vim/vim/commit/93f72cc119c796f1ccb75468ef9e446cbfb41e9b

"terminal" and "popup" buffer types cannot be tested, and commenting
them out causes an error, so just remove them.