possible method error upper triangle

```
n, m = size(A)
A = sprand(Float64, 10, 5, 0.25)
λ = 1.0e-3

K1 = triu([sparse(1.0I,n,n) A; A' -λ^2 * I])
S1 = ldl(Symmetric(K1, :U))

K2 = [sparse(1.0I,n,n) A; A' -λ^2 * I]
S2 = ldl(Symmetric(K2, :U))

b = ones(m+n)

norm(S1 \ b - S2 \ b) # not zero
```

Hi! I think this may be a method error. Do we still need L521 - L577 ?