[llvm] [SimplifyCFG] Handle that first matched eq cond in if chain can be Extra condition. (PR #154007)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Compile-time impact: +0.2%
CTMark: https://llvm-compile-time-tracker.com/compare.php?from=65ffa53cb70909be4dbedacd9de9de0725161592&to=025a3bf8cce8ae7e9389a640526ec5fdb9dce15e&stat=instructions:u

https://github.com/llvm/llvm-project/pull/154007