Problem:    Long quickfix line is truncated for :clist.
Solution:   Allocate a buffer if needed.
https://github.com/vim/vim/commit/5f30e26f6946f0d0396499f91fbcfaa9d1f8acf7

Problem:    Allowing 'completefunc' to switch windows causes trouble.
Solution:   use "textwinlock" instead of "textlock".
https://github.com/vim/vim/commit/28976e2accf11591c60e8a658a9e03544f0408b2

Assert E565 instead of E578.

vim-patch:8.2.0670: cannot change window when evaluating 'completefunc'

Problem:    Cannot change window when evaluating 'completefunc'.
Solution:   Make a difference between not changing text or buffers and also
            not changing window.
https://github.com/vim/vim/commit/6adb9ea0a6ca01414f4b591f379b0f829a8273c0

vim-patch:8.2.5029: "textlock" is always zero

Problem:    "textlock" is always zero.
Solution:   Remove "textlock" and rename "textwinlock" to "textlock".
            (closes vim/vim#10489)
https://github.com/vim/vim/commit/cfe456543e840d133399551f8626d985e1fb1958

Problem:    Cannot use :vimgrep in omni completion, causing C completion to
            fail.
Solution:   Add the EX_LOCK_OK flag to :vimgrep. (closes vim/vim#7292)
https://github.com/vim/vim/commit/33aecb1f2c85711d53858b71f5f3c2cbe076435f

Cherry-pick Test_resize_from_copen() indent change from patch 8.2.1432.

Problem:    Not enough testing for movement commands.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#6313)
https://github.com/vim/vim/commit/bdd2c290d3cda69e0046c42f0c651f60bc510a16

Cherry-pick test_functions.vim changes from patch 8.2.0183.
Cherry-pick Test_normal18_z_fold() change from patch 8.2.0540.

Problem:    Insufficient testing for src/window.c.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#6345)
https://github.com/vim/vim/commit/5d3c9f8c2a0fc29ba4ac8e0f052378b64d9e3dd3

Cherry-pick test_tagjump.vim changes from patch 8.1.2373.

Problem:    Various Ex commands not sufficiently tested.
Solution:   Add more test cases. (Yegappan Lakshmanan, closes vim/vim#5673)
https://github.com/vim/vim/commit/818fc9ad143911b2faa0d7cee86724aa70a02080

Needs to assert E170 instead of E580 because patch 8.2.3486 has been
ported but patch 8.2.1183 hasn't.

Problem:    Some Ex code not covered by tests.
Solution:   Add test cases. (Yegappan Lakshmanan, closes vim/vim#5659)
https://github.com/vim/vim/commit/406cd90f1963ca60813db91c413eef4b1b78ee44

Problem:    Insufficient code coverage for ex_docmd.c functions.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#5618)
https://github.com/vim/vim/commit/9f6277bdde97b7767ded43a0b5a2023eb601b3b7

Cherry-pick Test_window_only() from patch 8.2.0203.
Cherry-pick a memory leak fix from patch 8.2.0399.

vim-patch:8.2.0212: missing search/substitute pattern hardly tested

Problem:    Missing search/substitute pattern hardly tested.
Solution:   Add test_clear_search_pat() and tests. (Yegappan Lakshmanan,
            closes vim/vim#5579)
https://github.com/vim/vim/commit/07ada5ff2fd8f22ed3233ae5c4ddf87c7b3f56fe

vim-patch:8.2.0250: test_clear_search_pat() is unused

Problem:    test_clear_search_pat() is unused.
Solution:   Remove the function. (Yegappan Lakshmanan, closes vim/vim#5624)
https://github.com/vim/vim/commit/4f5776c17cd86f904a7e2f92db297c73e28939b7

Problem:    Some code not covered by tests.
Solution:   Add test cases. (Yegappan Lakshmanan, closes vim/vim#5645)
https://github.com/vim/vim/commit/f0cee1971f5258ce61f8a4e6a04d35c1e625bb01

Cherry-pick Test_bunload_with_offset() from patch 8.2.0243