Access Violation with multithreading

The code (fairly reduced)
```[julia]
using Pkg
Pkg.activate(".")
using LinearAlgebra
using FFTW

function fun1()
cache = FFT_Cache(830) # simplified

for no in 1:13267
# @show no
execude_fft(cache)
# do stuff here, not required for error
end

return nothing
end

struct FFT_Cache{FFTplanT}
FFTVals1::Vector{ComplexF64}
FFTVals2::Vector{ComplexF64}
iFFTplan::FFTplanT
end

function FFT_Cache(size_FFT)
FFTVals1 = Vector{ComplexF64}(undef, size_FFT)
FFTVals2 = Vector{ComplexF64}(undef, size_FFT)
iFFTplan = plan_ifft(FFTVals1)
FFT_Cache{typeof(iFFTplan)}(FFTVals1, FFTVals2, iFFTplan)
end

function execude_fft(cache::FFT_Cache)
(; iFFTplan, FFTVals1, FFTVals2) = cache
valnumber = 1 # dummy value

FFTVals1[1:valnumber] .= 1 # dummy value
FFTVals1[valnumber+1:end] .= 0
mul!(FFTVals2, iFFTplan, FFTVals1) #<- commenting this line removes the stack overflow

return nothing # dummy value
end

# function call
FFTW.set_num_threads(1)
fun1() # works

FFTW.set_num_threads(8) # 4 seems to work
fun1() # stack overflow

```

results in this access violation:
```
Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.
Exception: EXCEPTION_ACCESS_VIOLATION at 0x688f888 -- .text at C:\Users\user\.julia\artifacts\b7dd1809d0626eac3bf6f97ba8ccfbb6cc63c509\bin\libfftw3-3.dll (unknown line)
in expression starting at C:\Users\user\path\test.jl:47
.text at C:\Users\user\.julia\artifacts\b7dd1809d0626eac3bf6f97ba8ccfbb6cc63c509\bin\libfftw3-3.dll (unknown line)
#2 at .\threadingconstructs.jl:404
unknown function (ip: 0000023cc9602972)
jl_apply at C:/workdir/src\julia.h:1879 [inlined]
start_task at C:/workdir/src\task.c:1092
Allocations: 700577 (Pool: 700003; Big: 574); GC: 1
```
when julia is started with `julia --threads="auto" --startup-file="no"` on windows.

```
julia> versioninfo()
Julia Version 1.9.2
Commit e4ee485e90 (2023-07-05 09:39 UTC)
Platform Info:
OS: Windows (x86_64-w64-mingw32)
CPU: 8 × 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-14.0.6 (ORCJIT, tigerlake)
Threads: 8 on 8 virtual cores
Environment:
JULIA_EDITOR = code
```
with FFTW 1.7.1

Either reducting the threads for FFTW or starting julia without threads solves this issue.

I'm not shure if this belongs here or in base. I will cross [post there](https://github.com/JuliaLang/julia/issues/50441#issue-1791654320).