insert UInt32 Hashvalue in reverse order on big endian machine

[SuzyWangIBMer]

Changelog category (leave one):

• Not for changelog (changelog entry is not required)

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

...

Fix Hashvalue order on big endian machine

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

Information about CI checks: https://clickhouse.com/docs/en/development/continuous-integration/

[alexey-milovidov]

If it is needed for serialized state compatibility, let's do it on ser/de, as it will be more efficient.

[alexey-milovidov]

Please add a comment in the code with the motivation.

[SuzyWangIBMer]

If it is needed for serialized state compatibility, let's do it on ser/de, as it will be more efficient.

I am open to any alternative solutions. The problem I see now is that to do it on ser/de, I need to know the index of the hashvalue stored in buf, I can see it is calculated using inline size_t place(HashValue x) const { return (x >> UNIQUES_HASH_BITS_FOR_SKIP) & mask(); }. Not sure if I am allowed to move this method to AggregationFunctionsNull.h. Any suggestion on the implementation?

[alexey-milovidov]

Sounds reasonable, thank you!

[SuzyWangIBMer]

Can someone merge this in, please?