another attempt to make the fragmentation test more robust for Windows

tests/fragmentation/tfragment_gc.nim

@@ -24,7 +24,7 @@ let occupiedOk = occ < 64 * 1024 * 1024
 if not occupiedOk:
   echo "occupied ", formatSize(occ)
 echo "occupied ok: ", occupiedOk
-let totalOk = total < 210 * 1024 * 1024
+let totalOk = total < 230 * 1024 * 1024
 if not totalOk:
   echo "total peak memory ", formatSize(total)
 echo "total ok: ", totalOk