[llvm] [LLVM] Automatically strip `-fno-lifetime-dse` from compile_commands.json (PR #124623)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> @thesamesam Is it feasible to add -fno-lifetime-dse (currently for all GCC builds [47f5c54](https://github.com/llvm/llvm-project/commit/47f5c54f997a59bb2c65abe6b8b811f6e7553456)) only when GCC-specific -flto is used?
> 
> I don't think any developer uses GCC LTO for compile_commands.json. So preventing -fno-lifetime-dse for non-LTO gcc builds suffices.
> 
> Then we don't need a change to this Python script.

I would heavily prefer that solution.

https://github.com/llvm/llvm-project/pull/124623