Merge branch 'cp/unit-test-reftable-block'

Merge branch 'cp/unit-test-reftable-block'

Another test for reftable library ported to the unit test framework.

* cp/unit-test-reftable-block:
  t-reftable-block: mark unused argv/argc
  t-reftable-block: add tests for index blocks
  t-reftable-block: add tests for obj blocks
  t-reftable-block: add tests for log blocks
  t-reftable-block: remove unnecessary variable 'j'
  t-reftable-block: use xstrfmt() instead of xstrdup()
  t-reftable-block: use block_iter_reset() instead of block_iter_close()
  t-reftable-block: use reftable_record_key() instead of strbuf_addstr()
  t-reftable-block: use reftable_record_equal() instead of check_str()
  t-reftable-block: release used block reader
  t: harmonize t-reftable-block.c with coding guidelines
  t: move reftable/block_test.c to the unit testing framework