Bugfix: MultiIterator batch priority guard #1941

Job	Run time
cargo-test-sbf (token/program)	20m 34s
test	0s
check	0s
cargo-test-sbf (instruction-padding/program, token/program-2022, token/program-2022-test)	31m 23s
cargo-test-sbf (associated-token-account/program, associated-token-account/program-test)	19m 22s
cargo-test-sbf (token-upgrade/program)	15m 31s
cargo-test-sbf (feature-proposal/program)	19m 7s
cargo-test-sbf (governance/addin-mock/program, governance/program)	22m 12s
cargo-test-sbf (memo/program)	15m 57s
cargo-test-sbf (name-service/program)	16m 7s
cargo-test-sbf (stake-pool/program)	25m 36s
cargo-test-sbf (single-pool/program)	17m 16s
	3h 23m 5s

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