[Bug 55656] New: user32:dialog - test_IsDialogMessage() fails in the hi-u8 and mx-MX locales on Windows

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=55656

Bug ID: 55656
           Summary: user32:dialog - test_IsDialogMessage() fails in the
                    hi-u8 and mx-MX locales on Windows
           Product: Wine
           Version: unspecified
          Hardware: x86-64
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: user32
          Assignee: [e-mail]
          Reporter: [e-mail]

user32:dialog - test_IsDialogMessage() fails in the hi-u8 and mx-MX locales on
Windows:

w10pro64-hi-u8:
dialog.c:869: Test failed: Got unexpected wparam 0x97ade5.
dialog.c:580: Test failed: Got unexpected wparam 0xfffd.

w10pro64-mx-MX:
dialog.c:867: Test failed: Got unexpected wparam 0x3f.
dialog.c:578: Test failed: Got unexpected wparam 0x3f.

See https://test.winehq.org/data/patterns.html#user32:dialog

The 'mx-MX' locale is a mix of locales and may indicate the test only succeeds
when all the Windows locales match. For reference, mx-MX uses the following
settings:

SystemDefaultLCID    0411
UserDefaultLCID    040c
ThreadLocale    0411
SystemPreferredUILanguages    0412,0409
UserDefaultUILanguage    0412
ThreadUILanguage    0412
KeyboardLayout    00000000040A0C0A
Country    231
ACP    932

A bisect shows that both sets of failures started with the commit below:

commit fe594a83d4a87fccaced20372a83ecb2ef28de6c
Author: Zhiyi Zhang 
Date:   Fri Aug 18 11:39:19 2023 +0800

user32/tests: Test IsDialogMessageA() converting ASCII WM_CHAR messages.