Note: The crash happens in the second test case when using uninitialized
memory, and therefore doesn't happen with ASAN.

Problem:    Not easy to filter the output of maplist().
Solution:   Add mode_bits to the dictionary. (Ernie Rael, closes vim/vim#10356)

https://github.com/vim/vim/commit/d8f5f766219273a8579947cc80b92580b6988a4b

Co-authored-by: Ernie Rael <errael@raelity.com>

Problem:    It is not easy to restore saved mappings.
Solution:   Make mapset() accept a dict argument. (Ernie Rael, closes vim/vim#10295)

https://github.com/vim/vim/commit/51d04d16f21e19d6eded98f9530d84089102f925

Co-authored-by: Ernie Rael <errael@raelity.com>

Problem:    maparg() does not indicate the type of script where it was defined.
Solution:   Add "scriptversion".

https://github.com/vim/vim/commit/a9528b39a666dbaa026320f73bae4b1628a7fe51

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

Problem:    Vim9: in script cannot set item in uninitialized list.
Solution:   When a list is NULL allocate an empty one. (closes vim/vim#8461)

https://github.com/vim/vim/commit/e65081d1b591f16dc6e380a830d87565c5eb7b03

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

Problem:
Some tests fail with $SHELL=fish #6172
Related: https://github.com/neovim/neovim/pull/6176

Solution:
Replace "echo -n" with "printf", because "echo" in sh may be provided
as a shell builtin, which does not accept an "-n" flag to avoid a
trailing newline (e.g. on macos). "printf" is more portable (defined by
POSIX) and it does not output a trailing newline by itself.
Fixes #6172

TODO:
Other test failures may be related to "session leader" issue: https://github.com/neovim/neovim/issues/2354
Checked by running `:terminal ./build/bin/tty-test` from Nvim with
`shell=/bin/fish` (inherited from `$SHELL`) and it indeed complains
about "process does not own the terminal". With `shell=sh` it doesn't complain. And
unsetting `$SHELL` seems to make `nvim` to fall back to `shell=sh`.

    FAILED   test/functional/terminal/tui_spec.lua @ 1017: TUI paste: terminal mode
    test/functional/terminal/tui_spec.lua:1024: Row 1 did not match.
    Expected:
      |*tty ready                                         |
      |*{1: }                                                 |
      |*                                                  |
      |                                                  |
      |{5:^^^^^^^                                           }|
      |{3:-- TERMINAL --}                                    |
      |{3:-- TERMINAL --}                                    |
    Actual:
      |*process does not own the terminal                 |
      |*                                                  |
      |*[Process exited 2]{1: }                               |
      |                                                  |
      |{5:^^^^^^^                                           }|
      |{3:-- TERMINAL --}                                    |
      |{3:-- TERMINAL --}                                    |

    To print the expect() call that would assert the current screen state, use
    screen:snapshot_util(). In case of non-deterministic failures, use
    screen:redraw_debug() to show all intermediate screen states.

    stack traceback:
        test/functional/ui/screen.lua:622: in function '_wait'
        test/functional/ui/screen.lua:352: in function 'expect'
        test/functional/terminal/tui_spec.lua:1024: in function <test/functional/terminal/tui_spec.lua:1017>

    FAILED   test/functional/terminal/tui_spec.lua @ 1551: TUI forwards :term palette colors with termguicolors
    test/functional/terminal/tui_spec.lua:1567: Row 1 did not match.
    Expected:
      |*{1:t}ty ready                                         |
      |                                                  |
      |*                                                  |
      |                                                  |
      |{2:^^^^^^^                                           }|
      |                                                  |
      |{3:-- TERMINAL --}                                    |
    Actual:
      |*{1:p}rocess does not own the terminal                 |
      |                                                  |
      |*[Process exited 2]                                |
      |                                                  |
      |{2:^^^^^^^                                           }|
      |                                                  |
      |{3:-- TERMINAL --}                                    |

    To print the expect() call that would assert the current screen state, use
    screen:snapshot_util(). In case of non-deterministic failures, use
    screen:redraw_debug() to show all intermediate screen states.

    stack traceback:
        test/functional/ui/screen.lua:622: in function '_wait'
        test/functional/ui/screen.lua:352: in function 'expect'
        test/functional/terminal/tui_spec.lua:1567: in function <test/functional/terminal/tui_spec.lua:1551>

Problem:  Need more state() tests
Solution: Add a few more tests for operater pending mode and register
          yank command

closes: vim/vim#12883

https://github.com/vim/vim/commit/8dabccd295271104ad5af0abc48e283d644cff59