[wasm] System.Data.Tests - add debug info, to help with the test failure (#56838)

[wasm] System.Data.Tests - add debug info, to help with the test failure (#56838)

`System.Data.Tests.AppDomainsAndFormatInfo.Bug55978` fails sometimes for
wasm:

```
Assert.Equal() Failure
Expected: 2
Actual:   3

Stack trace
   at System.Data.Tests.AppDomainsAndFormatInfo.Bug55978()
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
```

To debug the issue, this dumps some state when the test fails.

Issue: https://github.com/dotnet/runtime/issues/47968