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

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Decodetalkers 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.

Done, did me log the warning right?

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