Remove the experimental attribute from the tensor APIs

[tannergooding]

This removes the experimental attribute, marking the APIs as stable.

As part of that, I did a pass to do some minor analyzer suggested cleanup/improvements to the code, ensured that the IsPinned property is correctly tracked and passed throughout the tensor types, and ensured that TensorSpan/ROTensorSpan could implement the tensor interfaces.

[AustinWise]

Should the table at the end of this document be updated to note that the experimental attribute was removed in .NET 10:

https://github.com/dotnet/runtime/blob/main/docs/project/list-of-diagnostics.md

If so, you might want to also update SYSLIB5005 since experimental was removed from that API in #113021.

[Copilot]

Pull Request Overview

This PR removes the experimental attributes from the tensor APIs and associated types, indicating that these APIs have now reached stability. Key changes include:

• Removal of [Experimental(…)] attributes from files such as Tensor.cs, TensorSpan.cs, TensorSpanDebugView.cs, ITensor*.cs, and related files.
• Updates to constructors and method signatures to consistently pass the new pinned parameter where needed.
• Adjustments to compatibility suppressions and project files to reflect these API changes.

Reviewed Changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/tools/illink/src/linker/CompatibilitySuppressions.xml	Updated suppression entries to align with the removal of experimental attributes.
src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/Tensor_1.cs	Removed the experimental attribute from Tensor and adjusted constructor signatures.
src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpan_1.cs	Removed the experimental attribute and updated constructors to include the pinned parameter.
src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpanDebugView.cs	Removed the experimental attribute.
Other files	Similar removals of the experimental attribute and corresponding adjustments across different tensor APIs and supporting types.