Serializationtest support for random map scripts

[elexis]

Currently it is not possible to do serializationtests on random-map-scripts.

However most matches are played on RMS, so most out-of-sync errors become known on such maps.

Also most of the time we can't reproduce the OOS error otherwise, so we have to create the equivalent RMS map in atlas to do a serializationtestmatch with the provided replay file, which is a painful process.

We can generate the map once and then reuse that consecutively.

[wraitii]

Attached patch attempts this. It seems like the "map generation" part works correctly but there is an unknown OOS in the obstruction manager and I think also an OOS in a range manager (will create an upcoming ticket for that one).

It also stops the serializationtest from recreating the map every turn which was wasteful.

[elexis]

(About every OOS on rejoin is revealed in multiplayer lobby matches and those take place in the vast majority on random-map-matches. Having to create the equivalent scenario map consumes a lot of time, so this is an important bottleneck of OOS debugging.)