Multiplication of FFT plan and AbstractArray stack-overflows

https://github.com/JuliaMath/AbstractFFTs.jl/blob/03ef58b6f1fc033cba090a24c94837013b9f3ab0/src/definitions.jl#L220
This may be self-recursive

MWE
```julia
julia> f = ApproxFunBase.plan_transform(Chebyshev(), rand(4))
FastTransforms.ChebyshevTransformPlan{Float64, 1, (5,), false, 1, UnitRange{Int64}}(FFTW r2r REDFT10 plan for 4-element array of Float64
(redft10e-r2hc-4
(rdft-r2hc-direct-r2c-4 "r2cf_4")))

julia> f * rand(4,4)
ERROR: StackOverflowError:
Stacktrace:
[1] _copyto_impl!
@ ./array.jl:331 [inlined]
[2] copyto!
@ ./array.jl:322 [inlined]
[3] copyto!
@ ./array.jl:346 [inlined]
[4] circcopy!(dest::Matrix{Float64}, src::Matrix{Float64})
@ Base ./multidimensional.jl:1201
[5] copy1
@ ~/.julia/packages/AbstractFFTs/Wg2Yf/src/definitions.jl:50 [inlined]
[6] *(p::FastTransforms.ChebyshevTransformPlan{Float64, 1, (5,), false, 1, UnitRange{Int64}}, x::Matrix{Float64}) (repeats 79983 times)
@ AbstractFFTs ~/.julia/packages/AbstractFFTs/Wg2Yf/src/definitions.jl:220
```

Ideally this should lead to some other error, and not a stack overflow.