[automerger skipped] BidirectionalSequenceLSTM op: Adds layer norm support. am: ed5c004915 am: de5183ff14
am: 889b52c305 -s ours
am skip reason: change_id I72d029fef6d890eb1771c21814b028b09af280c7 with SHA1 f404a1e894 is in history

Change-Id: I8f702728d68a9dd5999ef53686b17bbccb68fe1a