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/terms/SignificantLongTermsTests.java
format,
                0
            );
            bucket.updateScore(significanceHeuristic);
            buckets.add(bucket);
        }
        return new SignificantLongTerms(name, requiredSize, 1L, metadata, format, subsetSize, supersetSize, significanceHeuristic, buckets);
    }
    @Override
    protected Class<ParsedSignificantLongTerms> implementationClass() {
        return ParsedSignificantLongTerms.class;
    }
    @Override
    protected InternalSignificantTerms<?, ?> mutateInstance(InternalSignificantTerms<?, ?> instance) {
        if (instance instanceof SignificantLongTerms longTerms) {
            String name = longTerms.getName();
            int requiredSize = longTerms.requiredSize;
            long minDocCount = longTerms.minDocCount;
            DocValueFormat format = longTerms.format;
            long subsetSize = longTerms.getSubsetSize();
            long supersetSize = longTerms.getSupersetSize();
            List<SignificantLongTerms.Bucket> buckets = longTerms.getBuckets();
            SignificanceHeuristic significanceHeuristic = longTerms.significanceHeuristic;
            Map<String, Object> metadata = longTerms.getMetadata();
            switch (between(0, 5)) {
                case 0 -> name += randomAlphaOfLength(5);
                case 1 -> requiredSize += between(1, 100);
                case 2 -> minDocCount += between(1, 100);
                case 3 -> subsetSize += between(1, 100);
                case 4 -> supersetSize += between(1, 100);