Problem:    Code for modeless selection not sufficiently tested.
Solution:   Add tests.  Move mouse code functionality to a common script file.
            (Yegappan Lakshmanan, closes vim/vim#5821)
https://github.com/vim/vim/commit/515545e11f523d14343b1e588dc0b9bd3d362bc2

Skip termcode tests for now.

Problem:    Some Normal mode commands not fully tested.
Solution:   Add a few more tests. (Yegappan Lakshmanan, closes vim/vim#7073)
https://github.com/vim/vim/commit/d1ad99b65470d3e754f6a0588a6b0dc2214a1eab

Cherry-pick test_registers.vim change from patch 8.2.0644.

Problem:    Various Normal mode commands not fully tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#7059)
https://github.com/vim/vim/commit/8a9bc95eaec53f4e0c951ff8f2686ae5113a5709

Cherry-pick Test_normal_gdollar_cmd() change from patch 8.2.0540.

Problem:    ml_get error when switching buffer in Visual mode.
Solution:   End Visual mode when switching buffer. (closes vim/vim#10902)
https://github.com/vim/vim/commit/cfeb8a584be11758cf71ae02f6c937b06d6bb66f

Problem:    Search code not sufficiently tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#5999)
https://github.com/vim/vim/commit/224a5f17c6ec9e98322a4c6792ce4f9bb31a4cce

Cherry-pick test_charsearch.vim change from patch 8.2.0448.
Cherry-pick test_search.vim changes from patch 8.2.0619.

Problem:    Channel and sandbox code not sufficiently tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#5855)
https://github.com/vim/vim/commit/ca68ae13114619df3e4c195b41ad0575516f5ff6

Cherry-pick test_clientserver.vim changes form patch 8.2.0448.

Problem:    Various Normal mode commands not fully tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#5751)
https://github.com/vim/vim/commit/1671f4488105ee12a6a8558ae351436c26ab55fc

Cherry-pick a fix from patch 8.2.3162.
Omit test_iminsert.vim as previous patches to that file are N/A, and
Nvim doesn't support iminsert=2 either, so that test isn't useful.

Problem:    Some Normal mode commands not tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#5746)
https://github.com/vim/vim/commit/f5f1e10d0d39890298cdf27f664d466c8872b87e

Omit Test_edit_forbidden(): change reverted in patch 8.2.0369.
Cherry-pick Test_normal_yank_with_excmd() from patch 8.2.0293.
Skip Test_normal_cursorhold_with_count().
Cherry-pick Test_star_register() from patch 8.2.0270.

Problem:    Accessing memory beyond the end of the line.
Solution:   Stop Visual mode when closing a window.
https://github.com/vim/vim/commit/3d51ce18ab1be4f9f6061568a4e7fabf00b21794

Problem:    Changing text in Visual mode may cause invalid memory access.
Solution:   Check the Visual position after making a change.
https://github.com/vim/vim/commit/7ce5b2b590256ce53d6af28c1d203fb3bc1d2d97