Removed custom MemoryPools for reading Arrow, ORC, and Parquet formats in ClickHouse.
Why it matters
Previously, custom MemoryPools were used to manage memory allocations when reading Arrow, ORC, and Parquet files. After the improvements introduced in PR #84082, all memory allocations are tracked uniformly. This makes the specialized MemoryPools redundant, simplifying memory management and reducing maintenance overhead.How to use it
This change is internal and automatic. Users do not need to enable or configure anything to benefit from this improvement; the custom MemoryPools have been removed in the background during file format reading.