Split from https://gitlab.winehq.org/wine/wine/-/merge_requests/551.
-- v3: win32u: Broadcast WM_DISPLAYCHANGE message on display settings change. win32u: Lock display devices mutex in find_adapter. win32u: Use find_adapter_device_by_(name|id) helpers in find_adapter. win32u: Factor out display_device lookup in separate helpers. winemac.drv: Stop using the cached_modes_mutex for get_default_bpp. win32u: Move enumeration of available modes out of graphics drivers. user32/tests: Cleanup sysparams WM_DISPLAYCHANGE tests.