[llvm] [SLP][NFC] Remove useless code of deleting ExtractElementInst (PR #106697)

[Alexey Bataev via llvm-commits]

alexey-bataev wrote:

> > removeInstructionsAndOperands works only for vectorized scalars. adjustExtracts handles extractelements, which are not vectorized, part of buildvector
> 
> The `extractelements` of `buildvector` are operators of vectorized scalars. Should `removeInstructionsAndOperands` have already handled this correctly?

No, they are still part of the buildvector, it's just SLP vectorizer is smart enough to vectorize them. removeInstructionsAndOperands works only for the scalars, which part of the Vectorize nodes

https://github.com/llvm/llvm-project/pull/106697