tests: shorten the animation in the Scissor scenes

Scissor1.qml and Scissor2.qml rotate a 2D Image inside the 3D scene
with a 4000 ms animation. The grabber runs animations in consistent
timing mode, so this takes four seconds of wall time on every backend,
and the grabber gives up after six seconds total, three identical
200 ms grabs included. That leaves too little room for process start
and first-frame shader compilation: on Windows with D3D11 both scenes
have failed with "timed out waiting for scene to stabilize" in every
run since August. Locally the scenes need 4.9 s to settle, against
0.9 s for a static scene.

Use 200 ms like every other animated baseline scene. The image ends at
360 degrees, which is where it started, so the rendered result is
pixel-identical and no baselines change.

Pick-to: 6.12
Change-Id: I2635f0b7f26d58936faba89c53e4507b6d5631fa
Reviewed-by: Christian Strømme <christian.stromme@qt.io>