Monitor whether ConfigureAwait(false) still problematic in specs

In https://github.com/corvus-dotnet/Corvus.Extensions/pull/53#pullrequestreview-344062016 @mwadams asked me to remove all `ConfigureAwait(false)` calls in specs. However, on further discussion, we now suspect this is no longer required. So we're going to try without it, and see how it goes. This work item is to keep track of the fact that we're monitoring this.