Fix abigen not supporting enhanced privacy for go #1102

Job	Run time
Code linters	3m 26s
Unit tests in ubuntu-20.04	29m 43s
Build Docker image	2m 27s
Run PEEPS tests	21m 23s
Acceptance tests (basic \|\| basic-raft \|\| (advanced && raft) \|\| networks/typical::raft)	20m 19s
Acceptance tests (basic \|\| basic-istanbul \|\| (advanced && istanbul && !block-heights) \|\| networks/typical::istanbul)	22m 34s
Acceptance tests (basic \|\| basic-istanbul \|\| (advanced && istanbul && !block-heights) \|\| empty-block-period \|\| block-reward \|\| networks/typical::qbft)	22m 11s
Acceptance tests (validator-management && networks/template::istanbul-3plus1)	8m 13s
Acceptance tests (validator-management && networks/template::qbft-3plus1)	8m 40s
Acceptance tests (multitenancy && networks/plugins::raft-multitenancy)	48s
Acceptance tests (migration && networks/template::istanbul-4nodes)	5m 37s
Acceptance tests (migration && networks/template::raft-4nodes)	5m 48s
Acceptance tests (basic \|\| networks/typical::raftmps)	16m 47s
Acceptance tests (basic \|\| networks/typical::istanbulmps)	22m 6s
Acceptance tests (basic \|\| networks/typical::qbftmps)	21m 38s
	3h 31m 40s

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