Reconciles Type.cs with CoreRT version for move to shared partition. (dotnet/coreclr...

Reconciles Type.cs with CoreRT version for move to shared partition. (dotnet/coreclr#10306)

* Clone files and add resource strings.

* Subset each partial class.

* String=>string and Environment.GetResourceString => SR.cs

Doing this upfront with reduce the upcoming diffs - hopefully.

* Add IsRuntimeImplemented() emulator.

* One method was put in the wrong file. Correcting.

* Converted Type.Enum.cs to CoreRT style member by member.

* Converted Type.Helpers.cs to CoreRT style member by member.

* Internalize __Filter.cs into Type.Helpers.cs

* Pretransform to reduce diffs.

Removed contracts and comments,
"abstract public" -> "public abstract"

* Converted Type.cs to CoreRT style member by member.

* Eh.. rather not share IsInterface and IsSerializable than have that #if CORECLR.

* Transplant the CoreRt files (now just a reordering.)

Commit migrated from https://github.com/dotnet/coreclr/commit/7c77fffac0ea7399a2f7dbf217b5ea804c0c1ad0