Add SplitContainer to the integration test in DemoConsole

[Tanya-Solyanik]

Please add an integration test for Porting SplitContainerDesigner/SplitterPanelDesigner/SplitterDesigner. by dreddy-work · Pull Request #9320 · dotnet/winforms (github.com)

This PR provides a copy of our designer component in the runtime and thus enables developers to write their own IDE, like this one - winforms/src/System.Windows.Forms/tests/IntegrationTests/DesignSurface at main · dotnet/winforms · GitHub.

Please add SplitContainer control to the MainForm.cs file. Feel free to select the most appropriate tab, or to add a new Tab.

[MelonWang1]

Verified this issue in the latest .NET 8.0 SDK build: 8.0.100-preview.7.23328.8 on winforms repo, it was fixed. The SplitContainer is in the DemoConsle integration test. Screenshot as below:

[Nora-Zhou01]

Verified this on .NET 8.0 TP build: 8.0.100-preview.6.23328.9, the SplitContainer is in the DemoConsle integration test. result is same as above test result.

[dmitrii-drobotov]

@MelonWang1 @Nora-Zhou01 I just noticed that if I try to move splitter left or right on this added SplitContainer in the DemoConsole app, the app crashes with a StackOverflowException. Can you also reproduce it? If yes, could you create an issue for it?

[Nora-Zhou01]

@dmitrii-drobotov Yes, you are right, the DemoConsole application crashes when moving the SplitContainer splitter size. Created issue : #9410

[John-Qiao]

Verified this issue on winforms repo with DemoConsole test app from release/8.0-preview7 branch, it was fixed. Test result is same as above.