Testing gradient tool

[0HyperCube]

• Drawing on offset documents (Add tests for gradient drawing with transformations #2481)
• Shift to snap to 15 degrees (Add tests for gradient drawing with transformations #2481)
• Double click to insert a gradient stop (Add Gradient tool test for double clicking to insert a gradient stop #2527)
• Dragging the stop rearranges the ordering (Add Gradient tool test for dragging the stop rearranges the ordering #2565)
• Dragging an endpoint sets the correct point in the viewport (Add Gradient tool test for dragging an endpoint setting the correct point in the viewport #2564)
• Select and delete removes a stop, which is currently broken by this PR so this also needs to be fixed