Our sal/cppunittester/cppunittester.cxx uses SAL_IMPLEMENT_MAIN, so forwards the
cmd line args to osl_setCommandArgs.  CppunitTest_libreofficekit_tiledrendering
(run via that cppunittester) starts LOK, which starts SVMain on a lo_startmain
thread, which calls deskopt::DispatchWatcher::executeDispatchRequests to process
any cmd line arg requests to open documents.  It sees the
libtest_libreofficekit_tiledrendering.so (or .dylib/.dll) passed to
cppunittester, and tries to open it as a LO document.  Type detection will
typically determine it is plain text that should be opened with Writer, which
will succeed.  But when the .so is built with GCC 6, it happens to be detected
as a MacPaint document, loading which fails, so that executeDispatchRequests
(desktop/source/app/dispatchwatcher.cxx) will call xDesktop->terminate(), which
unwinds that lo_startmain thread (DeInitVCL etc.).  But the main cppunittester
thread is still calling into LOK, which is under the assumption that VCL etc. is
still functional, and somewhat random crashes will happen.

Change-Id: Ie7b00e797a0f3223b3942bb63a31aa9c44370247