Virtual AttributeType property and signature generic types (dotnet/coreclr#19818)

Virtual AttributeType property and signature generic types (dotnet/coreclr#19818)

* Virtual AttributeType property and signature generic types

https://github.com/dotnet/corefx/issues/31614

1. This will allow Reflection providers the option
to supply the attribute type without building
an entire constructor.

https://github.com/dotnet/corefx/issues/31798

2. This will permit other Reflection providers
to support Type.MakeGenericMethodParameter()
in their implementations.

* More robust argument validation.

* Change parameter name

Commit migrated from https://github.com/dotnet/coreclr/commit/a1cb8f6e39ba93d21f2fc2bd0405b9d6d28b42ee