add util for loss spike save and decode. #3319

Job	Run time
dlrover-python-test	17m 56s
atorch-python-test	5m 43s
atorch-pre-commit	2m 45s
brain-test	1m 38s
dlrover-system-test-criteo-deeprec	2m 44s
dlrover-system-test-deepfm	2m 49s
dlrover-system-test-tf2	1m 18s
operator-test	1m 35s
pre-commit	1m 28s
tfplus-pre-commit	1m 17s
tfplus-python-test	7s
	39m 20s

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