[llvm] [AArch64][GlobalISel] Add a constant funnel shift post-legalizer combine. (PR #151912)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-s390x-linux` running on `systemz-1` while building `llvm` at step 4 "build stage 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/42/builds/6743

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

```
Step 4 (build stage 1) failure: 'ninja -j4' (failure)

```

</details>

https://github.com/llvm/llvm-project/pull/151912