Blacklisting autotests

As of Qt 5.4, you can provide a BLACKLIST file for auto tests. It is mainly used to mark tests that are "flaky" (i.e. sometimes PASSing sometimes FAILing), in order for Qt's CI system to ignore their failures.

See http://code.qt.io/cgit/qt/qtbase.git/tree/src/testlib/qtestblacklist.cpp for more information.