Steps to reproduce:
1. Open user attached pro
2. Open LAYOUT scene
3. Click play
4. Notice the extended loading time
5. If the scene does not crash, stop it, duplicate the cubes in the scene, rebake the navmesh
6. Play the scene
-Unity crashes at this point

#0 0x000001002c96e5 in drawOffMeshLinks(duDebugDraw*, NavMesh const&)
#1 0x000001002ced34 in DrawNavMeshGizmoImmediate()
#2 0x000001009b7fd9 in GizmoManager::DrawAllGizmos()
#3 0x00000100af0ebc in Camera::FinishRenderingEditorCamera()
#4 0x000001205ea712 in (wrapper managed-to-native) UnityEditor.Handles:Internal_FinishDrawingCamera (UnityEngine.Camera) + 0x92 (0x1205ea680 0x1205ea741) [0x1353cc000 - Unity Child Domain]
#5 0x000001205d8db9 in UnityEditor.Handles:DrawCameraStep2 (UnityEngine.Camera,UnityEditor.DrawCameraMode) + 0xf9 (0x1205d8cc0 0x1205d8ddd) [0x1353cc000 - Unity Child Domain]
...

Expected result: complex navmesh should not cause a crash

Reproduced in: 2017.2.0a4, 2017.1.0b10, 5.6.1p4, 5.5.4f1, 5.4.5p3

Fixed in: 2018.3.0a10, 2018.2.9f1, 2017.4.14f1 - an error is thrown informing the user that maximum OffMeshLink limit is exceeded