Merge branch 'jk/index-pack-w-more-threads'

Long ago, we decided to use 3 threads by default when running the index-pack task in parallel, which has been adjusted a bit upwards. * jk/index-pack-w-more-threads: index-pack: adjust default threading cap p5302: count up to online-cpus for thread tests p5302: disable thread-count parameter tests by default