Extremely long Spline Point will cause the editor to lose FPS and crash some machines

User Description:

A couple of times I've accidentally scaled a spline node to be huge, causing the spline to extend miles along its tangent.

This causes my PC to lock up.

My guess would be that there's no safety check being done when either drawing or performing some other iterative calculation on the spline which in this case extends hundreds of thousands of units.

The thing that causes the node to scale huge in the first place is that when it's scaled tiny, the widget becomes very sensitive so will scale huge with a very small mouse movement.

Steps to Reproduce

1. Open QA-Game
2. Create a new Actor class bp and open it
3. Add a Spline component
4. Compile and save
5. Place the bp into the level
6. Select the down-arrow in the top left of the Viewport > Enable 'Show FPS'
7. In the World Outliner, double-click the Sky Sphere to snap to a faraway view
8. Then select the spline bp in the World Outliner
9. Select it again to choose a spline point
10. Then drag the spline point outside of the skysphere

Results: As the spline point gets further away from the world origin, the editor will start to lose FPS (The editor will regain FPS by clicking off of the spline point but the FPS will drop again if the spline point is reselected)

Expected: For the editor to maintain a high FPS when a spline point is far from world origin

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Affects Versions4.9.24.11
Target Fix4.11
Fix Commit2772547
Main Commit2800829
CreatedNov 13, 2015
ResolvedNov 18, 2015
UpdatedJun 16, 2016