Refactor - Makes loader-v4 the default #12738

Job	Run time
cargo-test-sbf (token/program)	8m 25s
cargo-test-sbf (instruction-padding/program, token/program-2022, token/program-2022-test)	14m 57s
check	3m 13s
cargo-test-sbf (associated-token-account/program, associated-token-account/program-test)	9m 29s
test (token/cli, token/program, token/program-2022, associated-token-account/program, instruction...	21m 49s
cargo-test-sbf (token-upgrade/program)	8m 47s
test (single-pool/cli, single-pool/program)	18m 33s
cargo-test-sbf (feature-proposal/program)	9m 12s
test (token-upgrade/cli, token-upgrade/program)	16m 18s
cargo-test-sbf (governance/addin-mock/program, governance/program)	11m 57s
cargo-test-sbf (memo/program)	9m 48s
cargo-test-sbf (name-service/program)	8m 36s
cargo-test-sbf (stake-pool/program)	11m 52s
cargo-test-sbf (single-pool/program)	9m 25s
	2h 42m 21s

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