Merge branch 'tb/repack-max-cruft-size'

"git repack" learned "--max-cruft-size" to prevent cruft packs from growing without bounds. * tb/repack-max-cruft-size: repack: free existing_cruft array after use builtin/repack.c: avoid making cruft packs preferred builtin/repack.c: implement support for `--max-cruft-size` builtin/repack.c: parse `--max-pack-size` with OPT_MAGNITUDE t7700: split cruft-related tests to t7704