[release/9.0-staging] fix stack 2x2 tensor along dimension 1

[github-actions[bot]]

Backport of #108620 to release/9.0-staging

/cc @tannergooding @kasperk81

Customer Impact

• [x] Customer reported
• [ ] Found internally

https://github.com/dotnet/runtime/issues/108615. Incorrect results will be computed for StackAlongDimension

Regression

• [ ] Yes
• [x] No

This is a net new and in-preview API for .NET 9

Testing

Additional tests covering the relevant scenario were added.

Risk

Low. This is a net new API in .NET 9 and shipped as experimental.

Fixing it will help ensure developers can use the feature and provide feedback as part of stabilizing the API surface.

[dotnet-policy-service[bot]]

Tagging subscribers to this area: @dotnet/area-system-numerics-tensors See info in area-owners.md if you want to be subscribed.

[tannergooding]

CC. @jeffhandley

[tannergooding]

Removed servicing-consider temporarily as @MihaZupan pointed out that another line needs updating for the latter method to be correct. This likely means we also need another test to cover that overload