The following aggregation 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.

   * InternalAutoDateHistogramTests
   * InternalAvgTests
   * InternalDerivativeTests
   * InternalGeoCentroidTests
   * InternalWeightedAvgTests
   * SignificantLongTermsTests
   * SignificantStringTermsTests
server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalAutoDateHistogramTests.java
0,
            roundings,
            25
        );
        assertThat(result, equalTo(2));
    }
    @Override
    protected BuilderAndToReduce<InternalAutoDateHistogram> randomResultsToReduce(String name, int size) {
        long startingDate = randomLongBetween(0, utcMillis("2050-01-01"));
        RoundingInfo[] roundingInfos = AutoDateHistogramAggregationBuilder.buildRoundings(null, null);
        int roundingIndex = between(0, roundingInfos.length - 1);
        DocValueFormat format = randomDateDocValueFormat();
        List<InternalAutoDateHistogram> result = new ArrayList<>(size);
        for (int i = 0; i < size; i++) {
            long thisResultStart = startingDate;
            thisResultStart += usually() ? 0 : randomFrom(TimeUnit.MINUTES, TimeUnit.HOURS, TimeUnit.DAYS).toMillis(between(1, 10000));
            result.add(createTestInstance(name, null, InternalAggregations.EMPTY, thisResultStart, roundingInfos, roundingIndex, format));
        }
        return new BuilderAndToReduce<>(mock(AggregationBuilder.class), result);
    }
    @Override
    protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAutoDateHistogram> inputs) {
        int totalBucketConut = 0;
        long lowest = Long.MAX_VALUE;
        long highest = 0;
        for (InternalAutoDateHistogram histogram : inputs) {
            for (Histogram.Bucket bucket : histogram.getBuckets()) {
                long bucketKey = ((ZonedDateTime) bucket.getKey()).toInstant().toEpochMilli();
                if (bucketKey < lowest) {
                    lowest = bucketKey;