Make block_size of BuildHistKernel adaptive #16136

Job	Run time
Build CPU	11m 0s
Build CPU wheel for manylinux2014_aarch64	2m 23s
Build CUDA with RMM (dev)	11m 7s
Build CUDA with RMM	10m 38s
Build CPU wheel for manylinux2014_x86_64	1m 47s
Build CPU wheel for manylinux_2_28_aarch64	2m 54s
Build manylinux_2_28_aarch64 wheel	4m 22s
Build CUDA + manylinux_2_28_x86_64 wheel	12m 10s
Build CPU wheel for manylinux_2_28_x86_64	2m 4s
Build GPU-enabled R package	20m 33s
Run Python tests (multiple-gpu)	20m 44s
Run Google Tests with GPUs (Suite gpu-rmm, Runner linux-amd64-gpu)	5m 10s
Run Google Tests with GPUs (Suite mgpu, Runner linux-amd64-mgpu)	3m 1s
Run Google Tests with GPUs (Suite gpu, Runner linux-amd64-gpu)	5m 4s
Run Python tests (cpu-arm64)	1m 36s
Run Python tests (cpu-amd64)	15m 50s
Run Python tests (single-gpu)	20m 30s
	2h 30m 53s

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