No test for `bitarray.jl`

[inkydragon]

I find it odd that bitarray is not tested at all.
https://app.codecov.io/gh/JuliaLang/LinearAlgebra.jl/blob/master/src%2Fbitarray.jl

After some searching, the corresponding tests are currently in julialang/julia
https://github.com/JuliaLang/julia/blob/d269d7d375827a0279dc1fee7bb24c9418f06f03/test/bitarray.jl#L1644-L1705

We might migrate them over here.

[KristofferC]

We might migrate them over here.

Sounds like a good idea

[KristofferC]

I moved the tests but I am not sure that actually fixed the coverage...