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:    Various code not fully tested.
Solution:   Add a few more tests. (Yegappan Lakshmanan, closes vim/vim#6049)
https://github.com/vim/vim/commit/0ff5dedf0f69e56320199db7a2aad46be2a1f9b7

Nvim does not support encoding=latin1 or setting keycodes/termcaps.

Problem:    Test file has wrong name.
Solution:   Rename the file.  Various small fixes. (closes vim/vim#10674)
https://github.com/vim/vim/commit/bb404f5ad5ec909318bc24e5b82e4ed7b87ba8f4

Problem:    Various code not covered by tests.
Solution:   Add a few more test. (Yegappan Lakshmanan, closes vim/vim#7995)
https://github.com/vim/vim/commit/1f448d906b3c516e5864dc5bae3ddbf3664ee649

Cherry-pick some test_edit.vim changes from patches 8.2.{1022,1432}.
Reorder test_undo.vim to match upstream.

Problem:    Modifiers not simplified when timed out or using feedkeys() with
            'n" flag.
Solution:   Adjust how mapped flag and timeout are used. (closes vim/vim#10305)
https://github.com/vim/vim/commit/68a573ce2b996602a86b14d9b258ebb8c657604f

Problem:    Failure of mapping not checked for.
Solution:   Check return value of ins_typebuf(). (closes vim/vim#10299)
https://github.com/vim/vim/commit/12e21e387b5bbc928097abf1c189b7dc665838fc

Problem:    A key may be simplified to NUL.
Solution:   Use K_ZERO instead.  Use macros instead of hard coded values.
            (closes vim/vim#10290)
https://github.com/vim/vim/commit/17c95d9608370559441bb73941ba6d9a4b6b26bd