chore: add unit tests and cleanups #3186

Job	Run time
system-programs (account-compression, [ "cargo-test-sbf -p account-compression-test" ])	30s
system-programs (light-system-program, [ "cargo-test-sbf -p system-test -- --test-threads=1" ])	29s
system-programs (light-registry, [ "cargo-test-sbf -p registry-test -- --test-threads=1" ])	20s
system-programs (light-compressed-token, [ "cargo-test-sbf -p compressed-token-test -- --test-thr...	29s
system-programs (system-cpi-test, [ "cargo-test-sbf -p system-cpi-test -- --test-threads=1" ])	16s
system-programs (random-e2e-test, [ "RUST_MIN_STACK=8388608 cargo-test-sbf -p e2e-test -- --nocap...	17s
system-programs (token-escrow-test, [ "cargo test-sbf -p token-escrow -- --test-threads=1" ])	18s
	2m 39s

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