QWinTimeZonePrivate::ruleToData() uses full zone names as abbreviations

The windows implementation of access to time-zone information uses the same text (QWinTimeZonePrivate's m_daylightName or m_standardName) for both the abbreviated zone name (tran.abbreviation, in QWinTimeZonePrivate::ruleToData) and the display name of the zone (QWinTimeZonePrivate::displayName()'s return). This cannot be good.

I cannot see a way to get at zone abbreviations: although [0]'s example values suggest abbreviations, [1] says that

The StandardName and DaylightName members of the resultant TIME_ZONE_INFORMATION structure are localized according to the current user default UI language.

which strongly suggests the names returned are full names. In practice, experiment reveals that we get full names, not abbreviations, although these may be coming from the registry. Either way, we only have one source of names and we're using the names it gives both as full names and as abbreviations, which is not adequate.

• [0] https://msdn.microsoft.com/en-us/library/windows/desktop/ms725481(v=vs.85).aspx
• [1] https://msdn.microsoft.com/en-us/library/windows/desktop/ms724421(v=vs.85).aspx