Specialized GroupValues for primitive and large_primitive #16135

Is your feature request related to a problem or challenge?

After #15961, in GroupValuesPrimitive, we store the hash of group to speed up rehashing.

However, I found the bottleneck of rehashing is not hash computation, it is actually randomly access to the values.

So, after experimenting, the better is:

• We directly store the group value in map
• So, during probing we can perform eq in-place
• And, during rehashing we just perform the cheap hash computation for group value

But for the large primitives, it may be still better to store their hashes in map rather than themselves, otherwise it will make map too large and lead to possible regression.

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Additional context

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