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/metrics/InternalAvgTests.java
verifyAvgOfDoubles(largeValues, Double.NEGATIVE_INFINITY, 0d);
    }
    private void verifyAvgOfDoubles(double[] values, double expected, double delta) {
        List<InternalAggregation> aggregations = new ArrayList<>(values.length);
        for (double value : values) {
            aggregations.add(new InternalAvg("dummy1", value, 1, null, null));
        }
        InternalAvg internalAvg = new InternalAvg("dummy2", 0, 0, null, null);
        InternalAvg reduced = internalAvg.reduce(aggregations, null);
        assertEquals(expected, reduced.getValue(), delta);
    }
    @Override
    protected void assertFromXContent(InternalAvg avg, ParsedAggregation parsedAggregation) {
        ParsedAvg parsed = ((ParsedAvg) parsedAggregation);
        assertEquals(avg.getValue(), parsed.getValue(), Double.MIN_VALUE);
        
        if (avg.getCount() != 0) {
            assertEquals(avg.getValueAsString(), parsed.getValueAsString());
        }
    }
    @Override
    protected InternalAvg mutateInstance(InternalAvg instance) {
        String name = instance.getName();
        double sum = instance.getSum();
        long count = instance.getCount();
        DocValueFormat formatter = instance.getFormatter();
        Map<String, Object> metadata = instance.getMetadata();
        switch (between(0, 2)) {
            case 0:
                name += randomAlphaOfLength(5);