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
)
        );
        assertThat(docCounts(h), equalTo(Arrays.asList(1, 2, 1, 0, 1)));
    }
    public void testReduceBumpsInnerRange() {
        InternalAutoDateHistogram h = new ReduceTestBuilder(2).bucket("1970-01-01T00:00:01", 1)
            .bucket("1970-01-01T00:00:02", 1)
            .finishShardResult("s", 1)
            .bucket("1970-01-01T00:00:00", 1)
            .bucket("1970-01-01T00:00:05", 1)
            .finishShardResult("s", 5)
            .reduce();
        assertThat(keys(h), equalTo(Arrays.asList("1970-01-01T00:00:00Z", "1970-01-01T00:00:05Z")));
        assertThat(docCounts(h), equalTo(Arrays.asList(3, 1)));
    }
    public void testReduceBumpsRounding() {
        InternalAutoDateHistogram h = new ReduceTestBuilder(2).bucket("1970-01-01T00:00:01", 1)
            .bucket("1970-01-01T00:00:02", 1)
            .finishShardResult("s", 1)
            .bucket("1970-01-01T00:00:00", 1)
            .bucket("1970-01-01T00:01:00", 1)
            .finishShardResult("m", 1)
            .reduce();
        assertThat(keys(h), equalTo(Arrays.asList("1970-01-01T00:00:00Z", "1970-01-01T00:01:00Z")));
        assertThat(docCounts(h), equalTo(Arrays.asList(3, 1)));
    }
    private static class ReduceTestBuilder {
        private static final DocValueFormat FORMAT = new DocValueFormat.DateTime(
            DateFormatter.forPattern("date_time_no_millis"),
            ZoneOffset.UTC,