Rename variables named *parallel_distribution* to *nd_sbp* (1)

[terryzhao127]

Rename parallel_distribution to nd_sbp

[github-actions]

CI failed, removing label automerge

[github-actions]

CI failed, removing label automerge

[github-actions]

Speed stats:

GPU Name: GeForce GTX 1080 

PyTorch resnet50 time: 140.7ms (= 7037.1ms / 50, input_shape=[16, 3, 224, 224], backward is enabled)
OneFlow resnet50 time: 128.1ms (= 6407.0ms / 50, input_shape=[16, 3, 224, 224], backward is enabled)
Relative speed: 1.10 (= 140.7ms / 128.1ms)

PyTorch resnet50 time: 84.2ms (= 4212.1ms / 50, input_shape=[8, 3, 224, 224], backward is enabled)
OneFlow resnet50 time: 74.3ms (= 3714.3ms / 50, input_shape=[8, 3, 224, 224], backward is enabled)
Relative speed: 1.13 (= 84.2ms / 74.3ms)

PyTorch resnet50 time: 55.0ms (= 2748.1ms / 50, input_shape=[4, 3, 224, 224], backward is enabled)
OneFlow resnet50 time: 47.7ms (= 2383.5ms / 50, input_shape=[4, 3, 224, 224], backward is enabled)
Relative speed: 1.15 (= 55.0ms / 47.7ms)

PyTorch resnet50 time: 48.3ms (= 2413.1ms / 50, input_shape=[2, 3, 224, 224], backward is enabled)
OneFlow resnet50 time: 44.6ms (= 2227.5ms / 50, input_shape=[2, 3, 224, 224], backward is enabled)
Relative speed: 1.08 (= 48.3ms / 44.6ms)

PyTorch resnet50 time: 44.0ms (= 2200.7ms / 50, input_shape=[1, 3, 224, 224], backward is enabled)
OneFlow resnet50 time: 40.4ms (= 2021.1ms / 50, input_shape=[1, 3, 224, 224], backward is enabled)
Relative speed: 1.09 (= 44.0ms / 40.4ms)