remove obsolete encoding headers #4433

Job	Run time
pytorch_tutorial_build_worker (2, 15, linux.g5.4xlarge.nvidia.gpu)	41m 6s
pytorch_tutorial_build_worker (9, 15, linux.g5.4xlarge.nvidia.gpu)	19m 14s
pytorch_tutorial_build_worker (10, 15, linux.g5.4xlarge.nvidia.gpu)	18m 14s
pytorch_tutorial_build_worker (4, 15, linux.g5.4xlarge.nvidia.gpu)	38m 13s
pytorch_tutorial_build_worker (8, 15, linux.g5.4xlarge.nvidia.gpu)	28m 57s
pytorch_tutorial_build_worker (14, 15, linux.g5.4xlarge.nvidia.gpu)	27m 35s
pytorch_tutorial_build_worker (7, 15, linux.g5.4xlarge.nvidia.gpu)	21m 1s
pytorch_tutorial_build_worker (5, 15, linux.g5.4xlarge.nvidia.gpu)	24m 32s
pytorch_tutorial_build_worker (1, 15, linux.g5.12xlarge.nvidia.gpu)	16m 30s
pytorch_tutorial_build_worker (15, 15, linux.g5.4xlarge.nvidia.gpu)	29m 41s
pytorch_tutorial_build_worker (6, 15, linux.g5.4xlarge.nvidia.gpu)	23m 47s
pytorch_tutorial_build_worker (12, 15, linux.g5.4xlarge.nvidia.gpu)	22m 16s
pytorch_tutorial_build_worker (11, 15, linux.g5.4xlarge.nvidia.gpu)	17m 10s
pytorch_tutorial_build_worker (3, 15, linux.g5.4xlarge.nvidia.gpu)	23m 38s
pytorch_tutorial_build_worker (13, 15, linux.g5.4xlarge.nvidia.gpu)	30m 50s
pytorch_tutorial_build_manager	23m 54s
	6h 46m 38s

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