Some arithmetic functions fail after adding tags

[ChrisRackauckas]

#274 fixed an issue with muladd which only came up with tags were in play. The fix included adding a non-Void tag to every dual in the tests. In doing so it found 4 other instances where tests failed, though it actually boils down to two groups: division and hypot

https://github.com/ChrisRackauckas/ForwardDiff.jl/blob/patch-1/test/DualTest.jl#L361 https://github.com/ChrisRackauckas/ForwardDiff.jl/blob/patch-1/test/DualTest.jl#L447

[jd-lara]

Shouldn't this problem be solved with the definition of hypot in DiffRules.jl?

https://github.com/JuliaDiff/DiffRules.jl/blob/5a121b8ccb996525824160fc822c2a69d172662c/src/rules.jl#L86