APICompat: Attributes on parameters and generic types are not compared

[eerhardt]

With the linker-friendliness work in 5.0, we have been adding attributes to parameters and generic types to allow the ILLinker to flow reflection usages through our APIs.

See https://github.com/mono/linker/blob/master/docs/design/reflection-flow.md for more information.

However, APICompat is not complaining when the ref and the src files are out of date. This leads to developer errors in forgetting to update the ref files.

APICompat should compare the attributes on parameters and generic types, like it does types and methods today.

cc @safern