Testing simple join.
Thread 0 should finish before thread 1 starts.
Thread 0 iteration 0
Thread 0 iteration 1
Thread 0 iteration 2
Thread 0 iteration 3
Thread 0 iteration 4
Thread 0 done!
Thread 1 iteration 0
Thread 1 iteration 1
Thread 1 iteration 2
Thread 1 iteration 3
Thread 1 iteration 4
Thread 1 done!
Simple join test done.