[llvm] [AMDGPU][RFC] Combine asm and disasm tests. (PR #92895)

[Ivan Kosarev via llvm-commits]

kosarev wrote:

> the use of sed means this can no longer run on Windows.

Somehow I see the Windows buildbot running the updated test for this very pull request.

https://buildkite.com/llvm-project/github-pull-requests/builds/65874#018f9ad8-c589-403d-a0cb-750c165811df
```
PASS: LLVM :: MC/AMDGPU/gfx12_asm_vop1.s (31915 of 53384)
```

I also see other tests using sed running on the bot and having no excluding directives. For one example:

```
PASS: LLVM :: CodeGen/AMDGPU/tid-mul-func-xnack-any-on-1.ll (8817 of 53384)
```

https://github.com/llvm/llvm-project/pull/92895