[llvm] [llvm-cgdata] Remove GENERATE_DRIVER option (PR #100077)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> Is there any discussion or docs about `Opt` vs `cl`? Are there plans to deprecate `cl` in the future? For a simple tool like this, I appreciate the simplicity of `cl` since all the code lives in one file and subcommands are handled really well.
> 
> If we must use `Opt`, maybe we can first detect the subcommand and parse the tool different depending on that subcommand. This might require duplicate code for options that are shared between subcommands.

`cl::opt` has some unusual option parsing behaviors, which make it not ideal as a user-facing tool. https://lists.llvm.org/pipermail/llvm-dev/2021-July/151622.html
https://reviews.llvm.org/D105532 and similar patches have migrated LLVM binary utilities to use `OptTable`, which avoids these problems.

https://github.com/llvm/llvm-project/pull/100077