Complete a test for QFilePrivate::fileName offset on Linux

This extends the test suite introduced in 497f0af1f7 for
a known-to-be-good case also for 32 bit systems.

Change-Id: Ia231bcb9b0102c28483d932be18767662b7a6afd
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

tests/auto/other/toolsupport/tst_toolsupport.cpp

@@ -114,7 +114,7 @@ void tst_toolsupport::offsets_data()
     if (sizeof(void *) == 8) {
         QTestData &data = QTest::newRow("QFilePrivate::fileName")
                 << pmm_to_offsetof(&QFilePrivate::fileName);
-        data << -1 << 248;
+        data << 168 << 248;
     }
 #endif