Right-click menu glitches in console vim

## Information

**VIM version**

```
VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Nov 19 2020 07:49:24)
Included patches: 1-1913
```

Operating System: Debian testing

## What went wrong

The right-click popup menu in console (not gui) vim glitches because of two bugs/limitations in upstream vim:
* [Async popup menu updates corrupt in console vim](https://github.com/vim/vim/issues/7537)
* [No submenus in popup menus in console vim](https://github.com/vim/vim/issues/7539)

https://user-images.githubusercontent.com/300342/103799763-d1596c80-504b-11eb-81f2-307e44fd6f51.mp4

The first issue is that the second entry is not `Refactor...` but `(None)` when opened for the first time and some old memory contents for the second time. The illegal memory access was fixed in https://github.com/vim/vim/commit/38455a921395a56690790c8c1d28c1c43ca04c8a, but the menu still isn't supposed to be updated asynchronously. Bram [says](https://github.com/vim/vim/issues/7537#issuecomment-751245376):

> You are not supposed to change the menu while it's being displayed. In
the GUI this may work, because it uses the library functions of the GUI
library. In the console we display the menu and it won't be updated
dynamically. The only thing the patch does is avoid crashing when the
menu is changed anyway.

ale doesn't change the number of entries in the PopUp menu itself, so with https://github.com/vim/vim/commit/38455a921395a56690790c8c1d28c1c43ca04c8a it should more or less work, but it'd still be better to do this synchronously, I think, just to be safe and to fix this in older versions of vim.

The second issue is better illustrated when running in vim with https://github.com/vim/vim/issues/7537 fixed:

https://user-images.githubusercontent.com/300342/103801429-036bce00-504e-11eb-9ec1-3d562c0c724f.mp4

Now the `Refactor...` entry is visible but it doesn't act as a submenu, so no refactors can be done in console vim. There is no reply in https://github.com/vim/vim/issues/7539 yet, but I did found a workaround:

```vim
anoremenu PopUp.Refactor\.\.\. :popup PopUp.Refactor
anoremenu PopUp.Refactor.A :echo "a"
anoremenu PopUp.Refactor.B :echo "b"
menu disable PopUp.Refactor
```

Both menus are visible in gvim, so this workaround must be only used in console vim.

## Reproducing the bug

1. Enable right-click popups:

```
set nocompatible
set mouse=a
set mousemodel=popup_setpos
```
2. Run vim with ale where some LSP is available & enabled.

3. Right click somewhere.

4. Popup appears, but the second entry is either corrupt (without https://github.com/vim/vim/issues/7537 fix) or not functional (with the fix but with https://github.com/vim/vim/issues/7539 still present).

### :ALEInfo

```

Current Filetype: python
Available Linters: ['bandit', 'flake8', 'jedils', 'mypy', 'prospector', 'pycodestyle', 'pydocstyle', 'pyflakes', 'pylama', 'pylint', 'pyls', 'pyre', 'pyright', 'vulture']
Enabled Linters: ['flake8', 'pyls']
Ignored Linters: []
Suggested Fixers:
'add_blank_lines_for_python_control_statements' - Add blank lines before control statements.
'autoimport' - Fix import issues with autoimport.
'autopep8' - Fix PEP8 issues with autopep8.
'black' - Fix PEP8 issues with black.
'isort' - Sort Python imports with isort.
'remove_trailing_lines' - Remove all blank lines at the end of a file.
'reorder-python-imports' - Sort Python imports with reorder-python-imports.
'trim_whitespace' - Remove all trailing whitespace characters at the end of every line.
'yapf' - Fix Python files with yapf.
Linter Variables:

let g:ale_python_auto_pipenv = 0
let g:ale_python_flake8_auto_pipenv = 0
let g:ale_python_flake8_change_directory = 'project'
let g:ale_python_flake8_executable = 'flake8'
let g:ale_python_flake8_options = ''
let g:ale_python_flake8_use_global = 0
let g:ale_python_pyls_auto_pipenv = 0
let g:ale_python_pyls_config = {'pyls': {'configurationSources': ['flake8']}}
let g:ale_python_pyls_executable = 'pyls'
let g:ale_python_pyls_use_global = 0
Global Variables:

let g:ale_cache_executable_check_failures = v:null
let g:ale_change_sign_column_color = 0
let g:ale_command_wrapper = ''
let g:ale_completion_delay = v:null
let g:ale_completion_enabled = 0
let g:ale_completion_max_suggestions = v:null
let g:ale_disable_lsp = 0
let g:ale_echo_cursor = 1
let g:ale_echo_msg_error_str = 'Error'
let g:ale_echo_msg_format = '%code: %%s'
let g:ale_echo_msg_info_str = 'Info'
let g:ale_echo_msg_warning_str = 'Warning'
let g:ale_enabled = 1
let g:ale_fix_on_save = 1
let g:ale_fixers = {'elixir': ['mix_format']}
let g:ale_history_enabled = 1
let g:ale_history_log_output = 1
let g:ale_keep_list_window_open = 0
let g:ale_lint_delay = 200
let g:ale_lint_on_enter = 1
let g:ale_lint_on_filetype_changed = 1
let g:ale_lint_on_insert_leave = 0
let g:ale_lint_on_save = 1
let g:ale_lint_on_text_changed = 0
let g:ale_linter_aliases = {'gitcommit': ['mail']}
let g:ale_linters = {'elixir': [], 'markdown': ['proselint'], 'rst': ['proselint'], 'sh': ['shellcheck'], 'mail': ['proselint'], 'gitcommit': ['proselint'], 'python': ['flake8', 'pyls'], 'text': ['proselint']}
let g:ale_linters_explicit = 1
let g:ale_linters_ignore = {}
let g:ale_list_vertical = 0
let g:ale_list_window_size = 10
let g:ale_loclist_msg_format = '%code: %%s'
let g:ale_lsp_root = {}
let g:ale_max_buffer_history_size = 20
let g:ale_max_signs = -1
let g:ale_maximum_file_size = 524288
let g:ale_open_list = 0
let g:ale_pattern_options = v:null
let g:ale_pattern_options_enabled = v:null
let g:ale_set_balloons = 0
let g:ale_set_highlights = 0
let g:ale_set_loclist = 1
let g:ale_set_quickfix = 0
let g:ale_set_signs = 1
let g:ale_sign_column_always = 0
let g:ale_sign_error = '>>'
let g:ale_sign_info = '--'
let g:ale_sign_offset = 1000000
let g:ale_sign_style_error = '>>'
let g:ale_sign_style_warning = '--'
let g:ale_sign_warning = '--'
let g:ale_sign_highlight_linenrs = 0
let g:ale_statusline_format = v:null
let g:ale_type_map = {}
let g:ale_use_global_executables = v:null
let g:ale_virtualtext_cursor = 0
let g:ale_warn_about_trailing_blank_lines = 1
let g:ale_warn_about_trailing_whitespace = 1
Command History:

(executable check - success) pyls
(executable check - success) flake8
(finished - exit code 0) ['/bin/bash', '-c', '''flake8'' --version']

<<>>
3.8.4 (mccabe: 0.6.1, pycodestyle: 2.6.0, pyflakes: 2.2.0) CPython 3.9.1 on Linux
<<>>

(finished - exit code 0) ['/bin/bash', '-c', 'cd ''/home/tomi/bin'' && ''flake8'' --format=default --stdin-display-name ''/home/tomi/bin/battery-watch'' - < ''/tmp/vpdXP0C/1/battery-watch''']

<<>>

(started) ['/bin/bash', '-c', '''pyls''']
```