To avoid hanging or crashing the mongo shell process, the ReshardingTest fixture goes through some lengths to interrupt the reshardCollection command on mongos and join the background thread in the mongo shell which was running the reshardCollection command. The error from the background thread is still logged just in case there's a bug in the ReshardingTest fixture and the message happens to be useful. However, the logged error has led to some confusion for what truly caused the test to fail.

We should find a way to elide the self-induced interruption error or separate it more from the assertion failure error message which immediately follows it.