Reverts parts of https://github.com/neovim/neovim/pull/27674
LSP snippets typically do include tabs or spaces to add extra
indentation and don't rely on the client using `autoindent`
functionality.
For example:
public static void main(String[] args) {\n\t${0}\n}
Notice the `\t` after `{\n`
Adding spaces or tabs independent of that breaks snippets for languages
like Haskell where you can have snippets like:
${1:name} :: ${2}\n${1:name} ${3}= ${0:undefined}
To generate:
name ::
name = undefined
Specifically, functions that are run in the context of the test runner
are put in module `test/testutil.lua` while the functions that are run
in the context of the test session are put in
`test/functional/testnvim.lua`.
Closes https://github.com/neovim/neovim/issues/27004.
