add axiswise granularity to Float8Tensor #4023

Job	Run time
test (CPU 2.3, linux.4xlarge, torch==2.3.0 --index-url https://download.pytorch.org/whl/cpu, cpu) / linux-job	6m 4s
test (CPU 2.2.2, linux.4xlarge, torch==2.2.2 --index-url https://download.pytorch.org/whl/cpu "nu... / linux-job	4m 12s
test (CPU 2.4, linux.4xlarge, torch==2.4.0 --index-url https://download.pytorch.org/whl/cpu, cpu) / linux-job	7m 31s
test (CPU Nightly, linux.4xlarge, --pre torch --index-url https://download.pytorch.org/whl/nightl... / linux-job	8m 45s
test (CUDA 2.2.2, linux.g5.12xlarge.nvidia.gpu, torch==2.2.2 "numpy<2" , cuda, 12.1) / linux-job	16m 17s
test (CUDA 2.3, linux.g5.12xlarge.nvidia.gpu, torch==2.3.0, cuda, 12.1) / linux-job	23m 52s
test (CUDA 2.4, linux.g5.12xlarge.nvidia.gpu, torch==2.4.0, cuda, 12.1) / linux-job	32m 21s
test (CUDA Nightly (Oct 1), linux.g5.12xlarge.nvidia.gpu, --pre torch==2.6.0.dev20241001+cu121 --... / linux-job	49m 51s
	2h 28m 53s

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