Constraint axes are not visible in Physics Asset editor viewport

This is a regression from 4.16 as I was not able to repro this issue in //UE4/Release-4.16 at CL 3514769.

Repro:

1. Open QAGame in the editor
2. Open the physics asset called

   SK_Mannequin_PhysicsAsset

   and double click to open it

3. Press the Constraint button in the Toolbar

Result:
There are no constraint axes visible in the viewport. Pressing the Constraint button does not change this.

Expected:
Constraint axes are visible.