--op-collection misses layernorm

[FindHao]

The liger operator collection doesn't include layernorm because the operator collection either has an op or not. Since liger's layernorm is added into existing op folder, it is skipped in liger op-collection. We need to specifically include layernorm in both default and liger op collection.

[xuzhao9]

It makes sense to me to have overlapping op collections.