"test / with-external-deps" CI job is frequently failing

[justinmk]

Problem

The test / with-external-deps CI job is frequently failing:

/home/runner/work/neovim/neovim/src/nvim/lua/executor.c: In function ‘nlua_common_vim_init’:
/home/runner/work/neovim/neovim/src/nvim/lua/executor.c:596:5: error: implicit declaration of function ‘luv_set_thread’; did you mean ‘luv_set_thread_cb’? [-Werror=implicit-function-declaration]
  596 |     luv_set_thread(lstate, nlua_luv_thread_cfpcall);
      |     ^~~~~~~~~~~~~~
      |     luv_set_thread_cb
/home/runner/work/neovim/neovim/src/nvim/lua/executor.c:597:5: error: implicit declaration of function ‘luv_set_cthread’; did you mean ‘luv_set_thread_cb’? [-Werror=implicit-function-declaration]
  597 |     luv_set_cthread(lstate, nlua_luv_thread_cfcpcall);
      |     ^~~~~~~~~~~~~~~
      |     luv_set_thread_cb

Expected behavior

should be reliable