Move ZSTDMT_freeCCtx ownership branches and teardown ordering into Rust while
keeping the MT context, worker pool, synchronization, dictionary, and custom
allocator layouts private to C callbacks. Preserve the original factory and
round-buffer conditions, release jobs before destroying the pools, and keep
free-on-null compatible with the C API.
Test Plan:
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo test --manifest-path rust/Cargo.toml free_cctx --lib
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings
- ulimit -v 41943040; make -j1
ddidderr
907c3af89e