Fix portable IsReferenceOrContainsReference<T> for pointer types

[Sergio0694]

Overview

The IsReferenceOrContainsReferences(Type) method we use to polyfill on .NET Standard < 2.1 has a bug that was inherited from the portable implementation originally in the BCL, which causes pointer types or types containing pointer types to be reported as being reference types. This is caused by Type.IsValueType actually returning false in this case (for... Reasons? 🤷).

dotnet/CommunityToolkit.HighPerformance/Helpers/Internals/RuntimeHelpers.cs

Line 184 in 1a94430

private static bool IsReferenceOrContainsReferences(Type type)

There should be an additional check for pointer types, and also a workaround for IsValueType.