I'd previously understood CLDR's minimumGroupingDigits to mean the
most significant group must have that many digits. It turns out to
mean only that the first grouping separator doesn't get added unless
the more significant group has this many. Once we have one separator,
more can be added that do isolate a single digit.
In the process, I discover some of the prior arithmetic is incorrect;
it is now fixed. Added some basic testing, amended some existing
tests. In the process, fixed naming of some double validator tests.
Pick-to: 6.6 6.5
Fixes: QTBUG-115740
Change-Id: Ia6ce011ba72e72428b015ca22b97d815ebf751b2
Reviewed-by: Ievgenii Meshcheriakov <ievgenii.meshcheriakov@qt.io>
c5515f5eb1