make sure IDistanceCalculatorHolder and IVertexFitHolder retrieve tool before event loop

Significantly reduce the chance of a data race as documented in Moore#620 -- and as a result should make the throughput test more reliable.

Make sure that functors using IDistanceCalculatorHolder or IVertexFitHolder retrieve the tool they use during bind instead of during prepare -- i.e. trigger the creation of the tool in initialize instead of during the event loop.