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
new ArrayList<>(buckets),
                    targetBuckets,
                    bucketInfo,
                    FORMAT,
                    emptyMap(),
                    innerInterval
                )
            );
            buckets.clear();
            return this;
        }
        InternalAutoDateHistogram reduce() {
            assertThat("finishShardResult must be called before reduce", buckets, empty());
            return (InternalAutoDateHistogram) results.get(0).reduce(results, emptyReduceContextBuilder().forFinalReduction());
        }
    }
    private static long utcMillis(String time) {
        return DateFormatter.forPattern("date_optional_time").parseMillis(time);
    }
    private List<String> keys(InternalAutoDateHistogram h) {
        return h.getBuckets().stream().map(InternalAutoDateHistogram.Bucket::getKeyAsString).collect(toList());
    }
    private List<Integer> docCounts(InternalAutoDateHistogram h) {
        return h.getBuckets().stream().map(b -> (int) b.getDocCount()).collect(toList());
    }
    public void testCreateWithReplacementBuckets() {
        InternalAutoDateHistogram noInterval = createTestInstance();
        InternalAutoDateHistogram orig = new InternalAutoDateHistogram(
            noInterval.getName(),
            noInterval.getBuckets(),