[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

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