The following ILM tests all contain switch statements with branches that will never execute. The tests use a `between(x, y)` switch expression, but there are `case` values that are outside the randomised range. We need to fix these before #88739 can be merged. By "fix", I mean either remove the spurious cases, or if we actually want them, then extend the randomized range.

   * ActionConfigStatsTests
   * AllocateActionTests
   * CopyExecutionStateStepTests
   * RolloverActionTests
   * WaitForRolloverReadyStepTests

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ilm/RolloverActionTests.java
: null;
        return new RolloverAction(maxSize, maxPrimaryShardSize, maxAge, maxDocs, maxPrimaryShardDocs);
    }
    @Override
    protected Reader<RolloverAction> instanceReader() {
        return RolloverAction::new;
    }
    @Override
    protected RolloverAction mutateInstance(RolloverAction instance) throws IOException {
        ByteSizeValue maxSize = instance.getMaxSize();
        ByteSizeValue maxPrimaryShardSize = instance.getMaxPrimaryShardSize();
        TimeValue maxAge = instance.getMaxAge();
        Long maxDocs = instance.getMaxDocs();
        Long maxPrimaryShardDocs = instance.getMaxPrimaryShardDocs();
        switch (between(0, 3)) {
            case 0 -> maxSize = randomValueOtherThan(maxSize, () -> {
                ByteSizeUnit maxSizeUnit = randomFrom(ByteSizeUnit.values());
                return new ByteSizeValue(randomNonNegativeLong() / maxSizeUnit.toBytes(1), maxSizeUnit);
            });
            case 1 -> maxPrimaryShardSize = randomValueOtherThan(maxPrimaryShardSize, () -> {
                ByteSizeUnit maxPrimaryShardSizeUnit = randomFrom(ByteSizeUnit.values());
                return new ByteSizeValue(randomNonNegativeLong() / maxPrimaryShardSizeUnit.toBytes(1), maxPrimaryShardSizeUnit);
            });
            case 2 -> maxAge = randomValueOtherThan(
                maxAge,
                () -> TimeValue.parseTimeValue(randomPositiveTimeValue(), "rollover_action_test")
            );
            case 3 -> maxDocs = maxDocs == null ? randomNonNegativeLong() : maxDocs + 1;
            case 4 -> maxPrimaryShardDocs = maxPrimaryShardDocs == null ? randomNonNegativeLong() : maxPrimaryShardDocs + 1;
            default -> throw new AssertionError("Illegal randomisation branch");