Bug in factorization of non-monic univ polynomial

[KlausC]

The following test case is broken:

    P = ZZ{BigInt}[:x]
    x = monom(P)
    p = 2x^3 + 7x^2 + x + 1
    @test factor(p)[1][1] == p
    @test factor(p, 30)[1][1] == p(x^30)
    @test_broken factor(p, 40)[1][1] == p(x^40)

Needs investigation (error in algorithm or in implementation?)

[KlausC]

Could not be reproduced; checked up to p(x^400).

julia> versioninfo()
Julia Version 1.8.0
Commit 5544a0fab76 (2022-08-17 13:38 UTC)
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 12 × Intel(R) Core(TM) i7-10710U CPU @ 1.10GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-13.0.1 (ORCJIT, skylake)
  Threads: 8 on 12 virtual cores