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.

Co-authored-by: Elias Alves Moura <eliamoura.alves@gmail.com>
Co-authored-by: venkatesh <shariharanvenkatesh@gmail.com>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Co-authored-by: Vikas Raj <24727447+numToStr@users.noreply.github.com>
Co-authored-by: Steve Vermeulen <sfvermeulen@gmail.com>
Co-authored-by: Evgeni Chasnovski <evgeni.chasnovski@gmail.com>
Co-authored-by: rwxd <rwxd@pm.me>
Co-authored-by: casswedson <58050969+casswedson@users.noreply.github.com>

Problem:    Cannot use CTRL-A and CTRL-X on unsigned numbers.
Solution:   Add "unsigned" to 'nrformats'. (Naruhiko Nishino, closes vim/vim#6144)
https://github.com/vim/vim/commit/aaad995f8384a77a64efba6846c9c4ac99de0953

Problem:    Number increment/decrement does not work with 'virtualedit'.
Solution:   Handle coladd changing. (Christian Brabandt, closes vim/vim#6240,
            closes vim/vim#923)
https://github.com/vim/vim/commit/6c6be9e88d72a60ee279ccad73d018c534b71d66

Problem:    CTRL-A does not work with an empty line. (Alex)
Solution:   Decrement the end only once. (Hirohito Higashi, closes vim/vim#2387)
https://github.com/vim/vim/commit/5fe6bdf858a7f2f288d599ffb5efb3c08449c817

Problem:    Test files have inconsistant modelines.
Solution:   Don't set 'tabstop' to 2, use 'sts' and 'sw'.

https://github.com/vim/vim/commit/9e4d8215d386100ab660d7d11e6620fd148b605e

Problem:    Two test files for increment/decrement.
Solution:   Move the old style test into the new style test. (Hirohito
            Higashi, closes vim/vim#881)

https://github.com/vim/vim/commit/52df117df724a7ad20affdf15214d2df2e507dcc