Picked fallback font often has wider character support than the ranges it's configured for.
Desired behavior is to stop at the first character that doesn't belong to current mapping.
For example, in texts like "abc<some CJK sequence>abc" we'd want the same for both "abc" sequences,
as opposed to using fallback CJK font for trailing Latin range.
Signed-off-by: Nikolay Sivov <nsivov@codeweavers.com>