[llvm] [InstCombine] Fix buggy transform in foldNestedSelects; PR 71330 (PR #71489)

[via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
+; RUN: opt -O3 -S < %s | FileCheck %s
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goldsteinn wrote:

Just tried no success. Maybe I did it wrong but:
`opt -O3 -preserve-ll-uselistorder ...` -> reproduces (did w.o `-preserve-ll-uselistorder` as well)
`opt -passes="default<O3> -preserve-ll-uselistorder ..." reproduces (did w.o `-preserve-ll-uselistorder` as well)
`-passes=<all-O3-passes> -preserve-ll-uselistorder` -> no reproduction
`-passes=instcombine -preserve-ll-uselistorder <copy of IR going into instcombine before bug>` -> no reproduction

https://github.com/llvm/llvm-project/pull/71489