[test] call sphinx once per tutorial file #4404

Job	Run time
pytorch_tutorial_build_worker (1, 15, linux.g5.12xlarge.nvidia.gpu)	14m 33s
pytorch_tutorial_build_worker (5, 15, linux.g5.4xlarge.nvidia.gpu)	23m 42s
pytorch_tutorial_build_worker (2, 15, linux.g5.4xlarge.nvidia.gpu)	47m 47s
pytorch_tutorial_build_worker (3, 15, linux.g5.4xlarge.nvidia.gpu)	21m 59s
pytorch_tutorial_build_worker (8, 15, linux.g5.4xlarge.nvidia.gpu)	1h 4m 40s
pytorch_tutorial_build_worker (6, 15, linux.g5.4xlarge.nvidia.gpu)	46m 2s
pytorch_tutorial_build_worker (4, 15, linux.g5.4xlarge.nvidia.gpu)	34m 30s
pytorch_tutorial_build_worker (12, 15, linux.g5.4xlarge.nvidia.gpu)	59m 33s
pytorch_tutorial_build_worker (7, 15, linux.g5.4xlarge.nvidia.gpu)	34m 29s
pytorch_tutorial_build_worker (14, 15, linux.g5.4xlarge.nvidia.gpu)	1h 1m 46s
pytorch_tutorial_build_worker (10, 15, linux.g5.4xlarge.nvidia.gpu)	55m 54s
pytorch_tutorial_build_worker (11, 15, linux.g5.4xlarge.nvidia.gpu)	49m 59s
pytorch_tutorial_build_worker (9, 15, linux.g5.4xlarge.nvidia.gpu)	47m 42s
pytorch_tutorial_build_worker (15, 15, linux.g5.4xlarge.nvidia.gpu)	1h 11m 43s
pytorch_tutorial_build_worker (13, 15, linux.g5.4xlarge.nvidia.gpu)	1h 2m 44s
pytorch_tutorial_build_manager	0s
	11h 37m 3s

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