sched_handle_dataset()'s Data_data_jobArray case never freed
dataset->rows (the decoded xce_job_submit_t*) after sched_on_job_array()
consumed it -- free_Dataset() is an empty no-op for every table type, so
nothing else owned this call. One bounded leak per delivered array push.
Free it via the existing free_JobSubmit_ptr() teardown on both the
success and error path, mirroring the sibling list-shaped cases'
ownership-transfer convention.
Rewrote test_job_array_expand.c's init_job_array() fixture to
heap-allocate + strdup its fields (matching the real wire-decode shape)
since freeing the old stack/string-literal fixture crashed. Redelivery
test now builds a fresh descriptor per delivery, matching how a real
redelivery is always a freshly-decoded wire message.
Closes task 7.3 (job-array-single-wal-record), the last of the three
post-GO residual gaps reopened 2026-07-16.