QTest: support initMain() in QTEST_APPLESS_MAIN

The various macros that implement a test's main() call a test object
initMain() static function, except for QTEST_APPLESS_MAIN. Add it to it.

[ChangeLog][QtTest] initMain() is now also supported when using
QTEST_APPLESS_MAIN.

Change-Id: I46b1eae5ce3bb8c9a5aca525f193c9250e520c6d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/testlib/qtest.h

@@ -616,6 +616,7 @@ struct QtCoverageScanner
 int main(int argc, char *argv[]) \
 { \
     TESTLIB_SELFCOVERAGE_START(TestObject) \
+    QT_PREPEND_NAMESPACE(QTest::Internal::callInitMain)<TestObject>(); \
     TestObject tc; \
     QTEST_SET_MAIN_SOURCE_PATH \
     return QTest::qExec(&tc, argc, argv); \