chore: Delete unused brillig methods #6201

Job	Run time
build-nargo	2m 19s
build-noir-wasm	3m 55s
build-acvm-js	1m 40s
build-noirc-abi	2m 5s
ACVM JS (Browser)	1m 31s
ACVM JS (Node.js)	41s
noir-js-backend-barretenberg	42s
noirc_abi	42s
noir_codegen	1m 0s
Noir JS	1m 31s
Integration Tests (Browser)	5m 28s
noir_wasm	1m 20s
Integration Tests (Node)	3m 43s
End	1s
	26m 38s

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