[AArch64] Combine concat(binop, binop) into binop(concat, concat) (#89911)

This generalizes the existing combine for concat(radd, radd) to any
binops. For much the same reason as the existing code, pushing the
concat up through the tree are hopefully quicker (or the same) as the
existing two half-vector operations, and can help combine away the
concat.

GitOrigin-RevId: 76ea5feb1f12ab35547a3aa1bc1b84d4bca69aa7
3 files changed