Test warning: Don't know how to handle '...'

We need to remove all the warnings from the test suite, so that when a new warning appears we can tell if it's a real problem or something we can safely ignore. Currently there are too many warnings when running make check, and they might be hiding real bugs.

There is a warning in tst_OrientationTest::test_defaults()

QWARN : tst_OrientationTest::test_defaults() Don't know how to handle 'QList<QQmlError>', use qRegisterMetaType to register it.

There is a warning in tst_UCTheme::testThemesRelativePathWithParentNoVariablesSet():

QWARN : tst_UCTheme::testThemesRelativePathWithParentNoVariablesSet() Don't know how to handle 'QList<QQmlError>', use qRegisterMetaType to register it.

There is a warning in tst_Page::testAnchorToPage_bug1249386():

QWARN : tst_Page::testAnchorToPage_bug1249386() Don't know how to handle 'QList<QQmlError>', use qRegisterMetaType to register it.