This will ensure luacheck and busted are only installed when they're actually needed. This cuts total build time by over 50%. Closes https://github.com/neovim/neovim/issues/22797.
Eliminates lua-client and non-static libluv as test time dependencies Note: the API for a public lua-client is not yet finished. The interface needs to be adjusted to work in the embedded loop of a nvim instance (to use it to talk between instances)
This allows us to get rid of the separate "nvim-test" target
