[clang] [clang][NFC] Move Diags.isIgnored check later in checkForRedundantLoop (PR #141470)

[Shafik Yaghmour via cfe-commits]

https://github.com/shafik commented:

Can you elaborate in your summary.

I am guessing because the other checks are a lot cheaper and this overall improves performance?

https://github.com/llvm/llvm-project/pull/141470