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

The tests for "pq" part of reftable library got rewritten to use the unit test framework. * cp/unit-test-reftable-pq: t-reftable-pq: add tests for merged_iter_pqueue_top() t-reftable-pq: add test for index based comparison t-reftable-pq: make merged_iter_pqueue_check() callable by reference t-reftable-pq: make merged_iter_pqueue_check() static t: move reftable/pq_test.c to the unit testing framework reftable: change the type of array indices to 'size_t' in reftable/pq.c reftable: remove unnecessary curly braces in reftable/pq.c