The test class `KeywordFieldMapperTests` contains a switch statement with a branch that will never execute. The test uses a `between(x, y)` switch expression, but the `4` case is outside the randomised range. We need to fix this before #88739 can be merged. By "fix", I mean either remove the spurious case, or if we actually want it then extend the randomized range.
server/src/test/java/org/elasticsearch/index/mapper/KeywordFieldMapperTests.java
Exception e = expectThrows(MapperParsingException.class, () -> createDocumentMapper(fieldMapping(b -> {
            minimalMapping(b);
            b.field("time_series_dimension", true).field("normalizer", "my_normalizer");
        })));
        assertThat(
            e.getCause().getMessage(),
            containsString("Field [normalizer] cannot be set in conjunction with field [time_series_dimension]")
        );
    }
    public void testDimensionIndexedAndDocvalues() {
        {
            Exception e = expectThrows(MapperParsingException.class, () -> createDocumentMapper(fieldMapping(b -> {
                minimalMapping(b);
                b.field("time_series_dimension", true).field("index", false).field("doc_values", false);
            })));
            assertThat(
                e.getCause().getMessage(),
                containsString("Field [time_series_dimension] requires that [index] and [doc_values] are true")
            );
        }
        {
            Exception e = expectThrows(MapperParsingException.class, () -> createDocumentMapper(fieldMapping(b -> {
                minimalMapping(b);
                b.field("time_series_dimension", true).field("index", true).field("doc_values", false);
            })));
            assertThat(
                e.getCause().getMessage(),
                containsString("Field [time_series_dimension] requires that [index] and [doc_values] are true")
            );
        }