v1.9-rc1: regression in diagonal multiplication with 3-terms

[dlfivefifty]

julia> versioninfo()
Julia Version 1.9.0-rc1.1
Commit b1b388a6d1 (2023-03-08 14:14 UTC)
Platform Info:
  OS: macOS (x86_64-apple-darwin22.3.0)
  CPU: 4 × Intel(R) Core(TM) i5-7600K CPU @ 3.80GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-14.0.6 (ORCJIT, skylake)
  Threads: 1 on 4 virtual cores

julia> n = 10; *(Diagonal(ones(n)),Diagonal(1:n), Diagonal(ones(n)))
10×10 Matrix{Float64}:
 1.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0   0.0
 0.0  2.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0   0.0
 0.0  0.0  3.0  0.0  0.0  0.0  0.0  0.0  0.0   0.0
 0.0  0.0  0.0  4.0  0.0  0.0  0.0  0.0  0.0   0.0
 0.0  0.0  0.0  0.0  5.0  0.0  0.0  0.0  0.0   0.0
 0.0  0.0  0.0  0.0  0.0  6.0  0.0  0.0  0.0   0.0
 0.0  0.0  0.0  0.0  0.0  0.0  7.0  0.0  0.0   0.0
 0.0  0.0  0.0  0.0  0.0  0.0  0.0  8.0  0.0   0.0
 0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  9.0   0.0
 0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  10.0

This should return a Diagonal as in Julia v1.8:

julia> versioninfo()
Julia Version 1.8.3-pre.0
Commit d0156b5601 (2022-09-30 07:06 UTC)
Platform Info:
  OS: macOS (x86_64-apple-darwin21.6.0)
  CPU: 4 × Intel(R) Core(TM) i5-7600K CPU @ 3.80GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-13.0.1 (ORCJIT, skylake)
  Threads: 1 on 4 virtual cores

julia> n = 10; *(Diagonal(ones(n)),Diagonal(1:n), Diagonal(ones(n)))

10×10 Diagonal{Float64, Vector{Float64}}:
 1.0   ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅     ⋅ 
  ⋅   2.0   ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅     ⋅ 
  ⋅    ⋅   3.0   ⋅    ⋅    ⋅    ⋅    ⋅    ⋅     ⋅ 
  ⋅    ⋅    ⋅   4.0   ⋅    ⋅    ⋅    ⋅    ⋅     ⋅ 
  ⋅    ⋅    ⋅    ⋅   5.0   ⋅    ⋅    ⋅    ⋅     ⋅ 
  ⋅    ⋅    ⋅    ⋅    ⋅   6.0   ⋅    ⋅    ⋅     ⋅ 
  ⋅    ⋅    ⋅    ⋅    ⋅    ⋅   7.0   ⋅    ⋅     ⋅ 
  ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅   8.0   ⋅     ⋅ 
  ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅   9.0    ⋅ 
  ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅    ⋅   10.0

[N5N3]

close by JuliaLang/julia#49007