QIntValidator::validate() deems a trailing grouping character Acceptable

QIntValidator::validate() doesn't verify sanity of grouping separators.
One of its tests, tst_QIntValidator::validateFrench(), starts by verifying that "1 " is Acceptable, wherein the space is interpreted as a grouping character.
However, this should be Intermediate since it is not a well-formed numeric representation, although it is a legitimate prefix of valid input.

The design of the internal API between the validators and QLocale is unfortunately bad at handling this; QLocalePrivate's methods just return a bool rather than a validator state, or equivalent, so validateChars() or numberToCLocale() cannot tell its caller about the intermediate state. This API should be changed to support the validators better.