fix(quotedprintable): Fix assert in AsciiStringToQuotedPrintable during map cache generation

[xezon]

Merge with Rebase

• Fixes Crash after upgrading to C++20 in MSVC32 when loading maps with unusual characters in mapchache.ini #497

This change fixes asserts in AsciiStringToQuotedPrintable (and UnicodeStringToQuotedPrintable). Seen during map cache generation. I think user facing this did not cause bugs.

 	ucrtbased.dll!548c4586()	Unknown
 	[Frames below may be incorrect and/or missing, no symbols loaded for ucrtbased.dll]	
 	ucrtbased.dll!548cb672()	Unknown
 	ucrtbased.dll!548cb581()	Unknown
 	ucrtbased.dll!548cb933()	Unknown
>	generalszh.exe!AsciiStringToQuotedPrintable(AsciiString original) Line 98	C++
 	generalszh.exe!MapCache::writeCacheINI(bool userDir) Line 397	C++
 	generalszh.exe!MapCache::updateCache() Line 457	C++
 	generalszh.exe!isValidMap(AsciiString mapName, bool isMultiplayer) Line 1001	C++
 	generalszh.exe!SkirmishPreferences::getPreferredMap() Line 296	C++
 	generalszh.exe!SkirmishGameOptionsMenuInit(WindowLayout * layout, void * userData) Line 1374	C++
 	generalszh.exe!WindowLayout::runInit(void * userData) Line 117	C++
 	generalszh.exe!Shell::doPop(bool impendingPush) Line 717	C++
 	generalszh.exe!Shell::shutdownComplete(WindowLayout * screen, bool impendingPush) Line 765	C++
 	generalszh.exe!ScoreScreenShutdown(WindowLayout * layout, void * userData) Line 404	C++
 	generalszh.exe!WindowLayout::runShutdown(void * userData) Line 119	C++
 	generalszh.exe!Shell::pop() Line 419	C++
 	generalszh.exe!ScoreScreenSystem(GameWindow * window, unsigned int msg, unsigned int mData1, unsigned int mData2) Line 546	C++
 	generalszh.exe!GameWindowManager::winSendSystemMsg(GameWindow * window, unsigned int msg, unsigned int mData1, unsigned int mData2) Line 705	C++
 	generalszh.exe!GadgetPushButtonInput(GameWindow * window, unsigned int msg, unsigned int mData1, unsigned int mData2) Line 218	C++
 	generalszh.exe!GameWindowManager::winSendInputMsg(GameWindow * window, unsigned int msg, unsigned int mData1, unsigned int mData2) Line 724	C++
 	generalszh.exe!GameWindowManager::winProcessMouseEvent(GameWindowMessage msg, ICoord2D * mousePos, void * data) Line 919	C++
 	generalszh.exe!WindowTranslator::translateGameMessage(const GameMessage * msg) Line 242	C++
 	generalszh.exe!MessageStream::propagateMessages() Line 1112	C++
 	generalszh.exe!GameEngine::update() Line 1014	C++
 	generalszh.exe!Win32GameEngine::update() Line 90	C++
 	generalszh.exe!GameEngine::execute() Line 1096	C++
 	generalszh.exe!GameMain() Line 52	C++
 	generalszh.exe!WinMain(HINSTANCE__ * hInstance, HINSTANCE__ * hPrevInstance, char * lpCmdLine, int nCmdShow) Line 903	C++
 	generalszh.exe!invoke_main() Line 107	C++
 	generalszh.exe!__scrt_common_main_seh() Line 288	C++
 	generalszh.exe!__scrt_common_main() Line 331	C++
 	generalszh.exe!WinMainCRTStartup(void * __formal) Line 17	C++
 	kernel32.dll!7781fcc9()	Unknown
 	ntdll.dll!77bb82ae()	Unknown
 	ntdll.dll!77bb827e()	Unknown

The second commit refactors the code a bit.

TODO

• Add pull id to commits
• Replicate in Generals

[Skyaero42]

Looks good

[xezon]

Replicated in Generals without conflicts