fix: compare system packs in pipeline step 5

Step 5 built emulator packs one profile at a time, where two profiles never share a path. It now also builds each system pack that gathers several profiles and compares it with verify. The first run found five standalone MSX and ColecoVision packs where verify skipped the data tree of a profile the system filter left without files, and credited msx-emu's copies the pack never wrote. verify now places those trees too: 541 system packs, all equal.

tests/test_pack_destinations.py

@@ -189,6 +189,9 @@ class EveryEmulatorPackMatchesItsReport(unittest.TestCase):
         finally:
             os.chdir(previous)
         self.assertTrue(ok, out.getvalue())
+        # Packs of several profiles too: a placement rule that only goes
+        # wrong when two profiles share a path never meets in one profile.
+        self.assertIn("system packs compared, all equal", out.getvalue())
 
 
 if __name__ == "__main__":