[llvm] [Tests][LoopDistribute] Re-adding target triple in a test that was removed earlier to fix build errors (PR #82954)

[Florian Hahn via llvm-commits]

fhahn wrote:

Please try to shorten the commit title to be more concise, as per https://llvm.org/docs/DeveloperPolicy.html#commit-messages

> The title should be concise. Because all commits are emailed to the list with the first line as the subject, long titles are frowned upon. Short titles also look better in git log.

https://github.com/llvm/llvm-project/pull/82954