If I'm reading the following code correctly:

            OptionValues graalOptions = HotSpotGraalOptionValues.HOTSPOT_OPTIONS;
            // Setting -Dgraal.TieredAOT overrides --compile-for-tiered
            if (!TieredAOT.hasBeenSet(graalOptions)) {
                graalOptions = new OptionValues(graalOptions, TieredAOT, options.tiered);
            }
            graalOptions = new OptionValues(HotSpotGraalOptionValues.HOTSPOT_OPTIONS, GeneratePIC, true, ImmutableCode, true);

Then the last setting of graalOptions cancels any previous change, because we pass in HOTSPOT_OPTIONS instead of graalOptions.