clippy: static_mut_refs #16122

Job	Run time
cargo-test-sbf (token/program)	7m 8s
cargo-test-sbf (instruction-padding/program, token/program-2022, token/program-2022-test)	12m 36s
cargo-test-sbf (associated-token-account/program, associated-token-account/program-test)	8m 7s
cargo-test-sbf (token-upgrade/program)	7m 55s
cargo-test-sbf (feature-proposal/program)	7m 9s
cargo-test-sbf (governance/addin-mock/program, governance/program)	10m 45s
cargo-test-sbf (name-service/program)	7m 15s
cargo-test-sbf (stake-pool/program)	11m 0s
cargo-test-sbf (single-pool/program)	7m 59s
check	3m 50s
test (token/cli, token/program, token/program-2022, associated-token-account/program, instruction...	19m 14s
test (single-pool/cli, single-pool/program)	17m 55s
test (token-upgrade/cli, token-upgrade/program)	16m 25s
	2h 17m 18s

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