Reshape cache flash kernel to support HND layout

[wenscarl]

Make reshape_and_cache_flash kernel support both NHD and HND layout for kv_cache.
NHD: [num_blocks, block_size, num_heads, head_size]
HND: [num_blocks, num_heads, block_size, head_size]

[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