[llvm] [AggressiveInstCombine] Inline strcmp/strncmp (PR #89371)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

This caused a miscompile in ffmpeg for x86 platforms.

It's reproducible on both Linux and MinGW, for both i686 and x86_64. To reproduce on linux on x86:
```console
$ git clone https://github.com/ffmpeg/ffmpeg
$ mkdir ffmpeg-build
$ cd ffmpeg-build
$ ../ffmpeg/configure --cc=clang --samples=$(pwd)/../samples
$ make fate-rsync # download test samples
$ make -j$(nproc) fate-subtitles
```

The miscompilation lies in the object file `libavformat/subtitles.o`.

I presume we should revert this until the issue has been resolved?

https://github.com/llvm/llvm-project/pull/89371