Backport 1.8: argmin / findmin incorrect behaviour

[matbesancon]

Exactly the same issue as #93 since the other one was closed :/

julia> using SparseArrays

julia> direction = spzeros(3); direction[1] = 2
2

julia> argmin(direction) === nothing
true

it is a fairly major bug IMO, I'm surprised 1.8 wasn't tested for breaking changes on packages?

[matbesancon]

For completeness, this was resolved in SparseArrays main but not integrated in 1.8, should probably have a patch release?

[matbesancon]

ping @dkarrasch

[dkarrasch]

The fix has been backported to v1.8.4.