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

[Fangrui Song via llvm-commits]

MaskRay wrote:

@thesamesam Is it feasible to add -fno-lifetime-dse (currently for all GCC builds
https://github.com/llvm/llvm-project/commit/47f5c54f997a59bb2c65abe6b8b811f6e7553456) only when GCC-specific -flto is used?

Then we don't need a change to this Python script.

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