[llvm] [SLP] Fix crash on extractelement with out-of-bounds index.....Fixes … (PR #176918)

[Graham Hunter via llvm-commits]

huntergr-arm wrote:

> Hey , ... Sorry to ping , CI previously ran and failed on code formatting..... I’ve fixed the issue and the change is now reviewer-approved. Could someone with CI permissions please re-run CI? Thanks....

The formatting check currently shows as passed to me?

https://github.com/llvm/llvm-project/pull/176918