[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

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