Reshape cache flash kernel to support HND layout

[wenscarl]

NHD: [num_blocks, block_size, num_heads, head_size]
HND: [num_blocks, num_heads, block_size, head_size]
Many fast attention kernels only support HND layout for kv_cache and this PR make reshape_and_cache_flash kernel support both.

[github-actions]

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[WoosukKwon]

👀

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. @wenscarl please rebase it. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[github-actions]

This pull request has been automatically marked as stale because it has not had any activity within 90 days. It will be automatically closed if no further activity occurs within 30 days. Leave a comment if you feel this pull request should remain open. Thank you!

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @wenscarl.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[wenscarl]

@WoosukKwon could you review the changes? Thanks!

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @wenscarl.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork