tst_QMimeDatabase::inheritsPerformance() is not an unit test but a
performance test, so moving it from 'tests/auto/corelib/mimetypes/qmimedatabase'
to 'tests/benchmarks/corelib/mimetypes/qmimedatabase'
Change-Id: I59e84f61559023659f101666683870f2ca1d2034
Reviewed-by: David Faure (KDE) <faure@kde.org>
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>