[Misc] Clean up and consolidate LRUCache

[DarkLight1337]

LRUDictCache and LRUCache are fundamentally the same, so I merged them together. I also improved the existing type annotations to be more precise.

[github-actions]

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[comaniac]

Overall LGTM. Meanwhile I'd like to make sure the logic is the same when pinned items are not used. cc @alexm-neuralmagic

[comaniac]

Since mm hash cache doesn't need the pin logic, could we optimize this function when there's no pinned items? For example

if remove_pinned and self.pinned_items:
    ...
else:
    lru_key = ...

Also I'm wondering whether to use .popitem(last=False) would be better?

[DarkLight1337]

I think this optimization is somewhat unnecessary, as the first key will be returned if pinned_items is empty. So either way, we will check for the emptiness of pinned_items once.

[comaniac]

IIUC in the branch with remove_pinned is False, we iterative an entire cache anyways whatever pinned_items are empty or not?

[DarkLight1337]

The next() statement only consumes the first item in the generator comprehension, it doesn't consume the generator fully.

[comaniac]

Ah you're right. Miss the point that it's a generator. Should be good then