The test is extended the same way I previously extended the memccpy()
test to fix what is probably the same kind of bug.
PR: 291359
Reported by: Collin Funk <collin.funk1@gmail.com>
Fixes: 6fa9e7d8737548ef93c573387ce62402c368d486 (D42519)
See also: 61ed5748e4e9c7397fcb2638b442f46ac5c9e7c5 (D46051)
MFC after: 1 week