Anonymous functions that return anonymous functions error on deserialization.

[amitmurthy]

Originally reported at #19456 (comment)
Reproducing below:

julia> y = (x) -> (() -> x)
(::#1) (generic function with 1 method)

julia> g = y(1)

julia> g()
1

julia> io = IOBuffer()
IOBuffer(data=UInt8[...], readable=true, writable=true, seekable=true, append=fa
lse, size=0, maxsize=Inf, ptr=1, mark=-1)

julia> serialize(io, y)

julia> seekstart(io)
IOBuffer(data=UInt8[...], readable=true, writable=true, seekable=true, append=fa
lse, size=316, maxsize=Inf, ptr=1, mark=-1)

julia> deserialize(io) # crashes

Going through the history of changes to base/serialize.jl, commit e3bec2a#diff-aec7b7bfc3115e923e4137ad38876951 is the first one that causes the above failure.

cc: @JeffBezanson