Also made NukeExecution build in two separate steps (build then execute)
as for other execution. Otherwise it would instantly explode if I set
high speeds. high speeds in necessary for some tests.
It implied changing a bit some tests. This includes removing the test
that nukes.length == 0 in missile silo which had nothing to do there as
we are just checking cooldown. One test should test only one thing. Here
it was breaking because I changed the NukeExecution which made no sense.