feat(experimental): Implement comptime mut globals #6454

Job	Run time
build-nargo	2m 30s
build-noirc-abi	1m 54s
build-acvm-js	1m 41s
build-noir-wasm	3m 54s
ACVM JS (Browser)	1m 22s
ACVM JS (Node.js)	34s
noir-js-backend-barretenberg	51s
noirc_abi	1m 27s
Noir JS	1m 33s
noir_codegen	1m 3s
Integration Tests (Browser)	5m 54s
Integration Tests (Node)	3m 39s
noir_wasm	1m 55s
End	1s
	28m 18s

Provide feedback