[Revert + FIX Blackwell] layer_norm backward #25940

Job	Run time
Check file paths	1m 11s
Clone-linux / Check bypass / Check bypass	5s
Clone-linux / Clone Paddle	4m 5s
build docker images / Build docker	2m 22s
Mac-CPU / Check bypass / Check bypass	9s
Linux-IXUCA / Check bypass / Check bypass	6s
Linux-IXUCA / Build and Test	2m 43s
Mac-CPU / Build and test	26m 57s
Linux-XPU / Check bypass / Check bypass	4s
Linux-CPU / Check bypass / Check bypass	8s
Linux-DCU / Check bypass / Check bypass	6s
PR-CI-SOT / Check bypass / Check bypass	7s
Distribute-stable-build / Check bypass / Check bypass	5s
Linux-XPU / Build	36m 2s
Distribute-stable-build / Build	43m 0s
Linux-DCU / Build	53m 38s
PR-CI-SOT / Build and Test	55m 13s
Linux-CPU / Build and test	46m 17s
Linux-XPU / Test	30m 17s
Linux-NPU / Check bypass / Check bypass	5s
Linux-NPU / Test	7m 28s
Linux-DCU / Test	1h 37m 40s
	6h 47m 48s

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