[llvm] [SandboxVec][Legality] Don't vectorize when instructions repeat (PR #124479)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64le-linux-multistage` running on `ppc64le-clang-multistage-test` while building `llvm` at step 4 "build stage 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/76/builds/6528

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 4 (build stage 1) failure: 'ninja' (failure)
ninja: error: build.ninja:3963: multiple outputs aren't (yet?) supported by depslog; bring this up on the mailing list if it affects you


```

</details>

https://github.com/llvm/llvm-project/pull/124479