hn/reftable-coverity-fixes (was: What's cooking in git.git (Dec 2021, #06; Mon, 27))

> * hn/reftable-coverity-fixes (2021-12-22) 18 commits
>  - reftable: be more paranoid about 0-length memcpy calls
>  - reftable: add print functions to the record types
>  - reftable: make reftable_record a tagged union
>  - reftable: remove outdated file reftable.c
>  - reftable: implement record equality generically
>  - reftable: make reftable-record.h function signatures const correct
>  - reftable: handle null refnames in reftable_ref_record_equal
>  - reftable: drop stray printf in readwrite_test
>  - reftable: order unittests by complexity
>  - reftable: all xxx_free() functions accept NULL arguments
>  - reftable: fix resource warning
>  - reftable: ignore remove() return value in stack_test.c
>  - reftable: check reftable_stack_auto_compact() return value
>  - reftable: fix resource leak blocksource.c
>  - reftable: fix resource leak in block.c error path
>  - reftable: fix OOB stack write in print functions
>  - Merge branch 'hn/create-reflog-simplify' into hn/reftable-coverity-fixes
>  - Merge branch 'hn/reftable' into hn/reftable-coverity-fixes
>
>  Problems identified by Coverity in the reftable code have been
>  corrected.
>
>  Will merge to 'next'?
>  source: <pull.1152.v5.git.git.1640199396.gitgitgadget@gmail.com>