Add rand_tangent for types

[mzgubic]

So far

julia> ChainRulesTestUtils.rand_tangent(Float64)
ERROR: StackOverflowError:
Stacktrace:
     [1] rand_tangent(rng::Random._GLOBAL_RNG, x::Module)
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:50
     [2] (::FiniteDifferences.var"#3#5"{Random._GLOBAL_RNG, Core.TypeName})(field_name::Symbol)
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:51
     [3] map (repeats 2 times)
       @ ./tuple.jl:216 [inlined]
     [4] rand_tangent(rng::Random._GLOBAL_RNG, x::Core.TypeName)
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:50
     [5] (::FiniteDifferences.var"#3#5"{Random._GLOBAL_RNG, DataType})(field_name::Symbol)
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:51
     [6] map(f::FiniteDifferences.var"#3#5"{Random._GLOBAL_RNG, DataType}, t::NTuple{20, Symbol})
       @ Base ./tuple.jl:226
     [7] rand_tangent(rng::Random._GLOBAL_RNG, x::Type{Float64})
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:50
     [8] (::FiniteDifferences.var"#3#5"{Random._GLOBAL_RNG, Core.TypeName})(field_name::Symbol)
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:51
--- the last 6 lines are repeated 4152 more times ---
 [24921] map (repeats 4 times)
       @ ./tuple.jl:216 [inlined]
 [24922] rand_tangent(rng::Random._GLOBAL_RNG, x::Core.TypeName)
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:50
 [24923] (::FiniteDifferences.var"#3#5"{Random._GLOBAL_RNG, DataType})(field_name::Symbol)
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:51
 [24924] map(f::FiniteDifferences.var"#3#5"{Random._GLOBAL_RNG, DataType}, t::NTuple{20, Symbol})
       @ Base ./tuple.jl:226
 [24925] rand_tangent(rng::Random._GLOBAL_RNG, x::Type{Float64})
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:50
 [24926] rand_tangent(x::Type)
       @ FiniteDifferences ~/JuliaEnvs/ChainRulesTestUtils.jl/dev/FiniteDifferences/src/rand_tangent.jl:8

with this

julia> ChainRulesTestUtils.rand_tangent(Float64)
NoTangent()

Needed for JuliaDiff/ChainRulesTestUtils.jl#117

[mzgubic]

This is needed to work on Julia 1.0