These tests were failing rarely on my MacBook when there was some
activity in the background. Read: one of a thousand executions?
- sections.c missed the sorting based on thread ids. This worked as long as the master thread finished its section before the worker thread started the second one but failed if the master thread was put to sleep by the OS.
- The checks in single.c assumed that the master thread executes the single region which works most of the time because it is usually faster than the newly spawned worker thread.