Integration tests for #10420:
- Adds an `--overlayPopups` command-line argument to IntegrationTestApp
- Renames `TestAppFixture` -> `DefaultAppFixture`
- Adds additional `OverlayPopupsAppFixture`
- Runs ComboBox and Menu tests in both default and overlay popups mode
- VS keeps changing the `.sln` file
- Warning CA1815 PlatformGraphicsExternalImageProperties should override Equals Avalonia.Base (net6.0) \src\Avalonia.Base\Platform\PlatformGraphicsExternalMemory.cs 7 N/A
- Warning CA1823 Unused field 'ProximityPoints' Avalonia.Controls (net6.0) src\Avalonia.Controls\Presenters\ScrollContentPresenter.cs 18 N/A
- Warning CS0169 The field 'VulkanDemoControl._vkInstance' is never used GpuInterop samples\GpuInterop\VulkanDemo\VulkanDemoControl.cs 19 N/A
- Warning CS0169 The field 'VulkanDemoControl._api' is never used GpuInterop samples\GpuInterop\VulkanDemo\VulkanDemoControl.cs 20 N/A
- Warning CS0219 The variable 'isZooming' is assigned but its value is never used ControlCatalog (netstandard2.0) samples\ControlCatalog\Pages\GesturePage.cs 73 N/A
- Warning xUnit2004 Do not use Assert.Equal() to check for boolean conditions. Avalonia.IntegrationTests.Appium tests\Avalonia.IntegrationTests.Appium\WindowTests_MacOS.cs 267 N/A
Will hopefully make it a bit more obvious if it breaks in future: previously it was easier to miss as both `nth-child` and `nth-last-child` changed the foreground.