Mismatch in UpgradeTemplate data after playing a map with map.ini with custom upgrades

[helmutbuhler]

Mismatch reproduction steps according to @Caball009 on Discord.

Custom maps with a map.ini file may still overwrite default data such as UpgradeTemplate, which would almost certainly cause a mismatch on another map. I haven't verified, but I think with the following steps you can reproduce a mismatch:

1. Play a match with instance01 on a map with custom upgrades such as:

Upgrade Upgrade_AmericaTOWMissile 
  DisplayName        = UPGRADE:TOWMissile
  BuildTime          = 2.0
  BuildCost          = 0  ; 1200
  ButtonImage        = SSTowMissiles
  ResearchSound      = HumveeVoiceUpgradeTowMissiles
End

You could maybe use another upgrade that's faster and more convenient to test.

2. Play a match against instance02 that hasn't played any map yet; the second match should not use this same upgrade naturally.
3. Mismatch should happen the moment the upgrade is used.

[Caball009]

Thanks for creating an issue for this. I took the liberty of cleaning up the first post and title a bit.

The issue is somewhat similar to #856, but UpgradeTemplate has no override feature like ThingTemplate so this will be harder to fix.

[helmutbuhler]

@Caball009 Thanks for the description! I successfully reproduced a mismatch with it and also just pushed a PR that should fix it.