Reduce runtime for csuite handle locks testing

During the effort of reducing Evergreen Ubuntu build variant runtime effort in WT-4394 and WT-4410, the csuite test_wt4333_handle_locks was identified as the longest running non-compile task which took 12m 36s to finish in a recent commit build. It is understandable the current runtime is a outcome of the test design, would be great to have a review and see if there's possibility to reduce the runtime (say ~8m), to help achieving a reduced overall Makespan for WiredTiger Evergreen builds.