[3.11] gh-106844: Fix issues in _winapi.LCMapStringEx (GH-107832) (GH-107875)

* Strings with length from 2**31-1 to 2**32-2 always caused MemoryError,
   it doesn't matter how much memory is available.
* Strings with length exactly 2**32-1 caused OSError.
* Strings longer than 2**32-1 characters were truncated due to integer overflow bug.

Now strings longer than 2**31-1 characters caused OverflowError.
(cherry picked from commit 04cc01453db2f0af72a06440831637f8bf512daf)