[llvm] [SLP] NFC. Replace TreeEntry::setOperandsInOrder with VLOperands. (PR #113880)

[Han-Kuan Chen via llvm-commits]

HanKuanChen wrote:

Cannot work with `-Wl,-plugin-opt=-opt-bisect-limit=-1` and `-Wl,-plugin-opt=-print-before-pass-number=`?
`-Wl,-plugin-opt=-print-module-scope` is also useful.


https://github.com/llvm/llvm-project/pull/113880