[GEN][ZH] Fix replay header mismatch between builds using 32 bit or 64 bit wide time_t

[helmutbuhler]

Another day goes by, and another bug is discovered. But this time, it's not a bug in the retail version, but in our build with VS22.
The replay header contains (among other) these elements:

• starttime
• endtime
• number of frames
• mismatch flag
• quitEarly flag
• disconnect flag (for each player)
• replayName (string)

start and endtime are of type time_t. On VC6 this was 32-bit, but on newer compilers it's 64-bit. In order to remain compatible, we need to load and save them as 32-bit. This PR fixes that.

Now you may ask: Wait, why did we not notice until now? Why are replays working?
Well, the replayName syncs everything up. It's serialized with a special character to indicate its end, and since all other header elements very likely don't contain that character, the serialization is automatically fixed there. But all the replay header elements listed above are indeed parsed and written out corrupted. We also didn't notice that, because, as it turns out, all those elements are invisible to the user.

We should still fix it though, so we don't spread the internet with corrupted replays. I'd also like to use the mismatch flag to harvest some non-mismatched replays for automatic testing in the near future...

[xezon]

Looks good. Needs to be replicated in Generals.

[xezon]

This 64 bit time_t breaks GenTool replay uploads in VS 2022 builds, because it cannot read the replay header.

[xezon]

I locally replicated this change to Generals but I am unable to push this to the remote branch

"git" push --recurse-submodules=check --progress "helmutbuhler" refs/heads/fix_replay_header_sh:refs/heads/fix_replay_header_sh
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
ERROR: Permission to helmutbuhler/CnC_Generals_Zero_Hour.git denied to xezon.

[xezon]

Replicated in Generals. Looks good.