Expander crashes the app.

[Xiaoy312]

Describe the bug

Expander crashes with measure -inf, -inf

Steps to Reproduce

• Add Expander to the page
• Launch the app and navigate to that page

Expected behavior

No crash.

Screenshots

Uncaught Error: System.InvalidOperationException: [LayoutTransformControl-42322"PART_LayoutTransformer"/PART_LayoutTransformer: Invalid measured size -Infinity,-Infinity. NaN or Infinity are invalid desired size.
  at Windows.UI.Xaml.FrameworkElement.InnerMeasureCore (:56086/Windows.Foundation.Size availableSize) [0x000e2] in C:\agent\_work\1\s\src\Uno.UI\UI\Xaml\FrameworkElement.Layout.netstd.cs:97

Environment

NuGet Package(s): 6.1.0-build.186.g928c99f74d

Package Version(s): 

Device form factor:
- [x] macOS
- [x] WASM
- [ ] ios (?: not tested)
- [ ] android (?: not tested)
- [ ] uwp

Visual Studio 
- [ ] 2017 (version: )
- [x] 2019 (version: ) 
- [ ] 2019 Preview (version: )

Additional context

Known workaround: Replacing controls:LayoutTransformControl with a Border with same x:Name. And removing the RotateTransform and any visual state setters affecting the RotateLayoutTransform.

[eiadxp]

I can confirm this issue with Android also:

Java.Lang.IllegalStateException Message=View with id -1: crc64a5a37c43dff01024.Grid#onMeasure() did not set the measured dimension by calling setMeasuredDimension()