Put remainder of packed tests into last bundle when using estimated times

[ksuther]

When using time estimates, the remainder tests get put into a new bundle when exceeding the optimal execution time. For example, if you set numSims to 5, you end up with 5 fully packed bundles and 1 one smaller leftover bundle.

This means you end up running 6 simulators even though numSims is 5. The extra time waiting for the 6th simulator to start takes a while and at least in my tests takes longer than simply appending the remainder to the final bundle.

[ravimandala]

@ksuther, thanks for the PR. It would be great if you can add a test for this.