StackOverflow with * between non-concrete types

x-ref https://discourse.julialang.org/t/stackoverflowerror-mutablearithmetics-jump-variables/132629/5

```Julia
julia> include("test/dummy.jl")

julia> x = DummyBigInt[1 2; 3 4]
2×2 Matrix{DummyBigInt}:
 DummyBigInt(1)  DummyBigInt(2)
 DummyBigInt(3)  DummyBigInt(4)

julia> y = Any[x[1], x[2]]
2-element Vector{Any}:
 DummyBigInt(1)
 DummyBigInt(3)

julia> x * y
ERROR: StackOverflowError:
```