[llvm] [InstCombine] Fix #163110: Fold icmp (shl X, L), (add (shl Y, L), 1<<L) to icmp X, (Y + 1) (PR #165975)

[Hongyu Chen via llvm-commits]

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XChy wrote:

```suggestion
      I->->dropPoisonGeneratingFlags();
```

https://github.com/llvm/llvm-project/pull/165975