LLVM fails instruction selection for srem and ugt for <4 x i8> types on ptx.

[abadams]

This is causing buildbot failures on main. A bug was opened on LLVM here: llvm/llvm-project#69124

If that's not resolved soon, we'll need a workaround.

[abadams]

Was fixed upstream, and I have confirmed it is fixed for me locally.