xla

ea135c6d - Add feature to increase the number of host to device transfer threads (#4693)

Add feature to increase the number of host to device transfer threads (#4693) * Add feature to increase the number of host to device transfer threads * Revert test set batch_size to 64 * Rename the config name to OPTIMIZED_KWARGS_v4 * Change description to v4 instead of just v4-8 as this config imporves resnet performance even on v4 slices and pods * remove extra line * Add flag to switch v4 optimized config * Modify name to more generalized way to keep it open for v5 config as well * Add flexibility to define multiple configs based on TPU versions * Keep the command consistent