add support GetMultipleKeys #3977

Job	Run time
Basic Checks	1m 49s
Unit Tests	10m 48s
Integration Tests (raft)	14m 13s
Integration Tests (pvtdata)	13m 47s
Integration Tests (pvtdatapurge e2e)	23m 38s
Integration Tests (ledger)	15m 5s
Integration Tests (lifecycle)	7m 42s
Integration Tests (smartbft)	21m 39s
Integration Tests (discovery gossip devmode pluggable)	10m 17s
Integration Tests (gateway idemix pkcs11 configtx configtxlator)	19m 58s
Integration Tests (sbe nwo msp)	9m 42s
	2h 28m 38s

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