[clang-tools-extra] [clangd][modules] Remove the options that is for gcc, make modules work for clangd when using gcc (PR #200001)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

> > > automatically drop any unsupported command line argument.
> > 
> > 
> > Makes sense but we need to emit a warning
> 
> How to emit it? Should I use elog? or any other function?

`log("Warning: ....` seems fine to me.

https://github.com/llvm/llvm-project/pull/200001