Just got a bunch of instances of this suite timing out all on Windows agents. Could be a coincidence but seems unlikely.

**Build scan:**
https://gradle-enterprise.elastic.co/s/rvfpi7upehqjk/tests/:x-pack:plugin:esql:test/org.elasticsearch.xpack.esql.expression.function.scalar.nulls.CoalesceTests
**Reproduction line:**
```
null
```

**Applicable branches:**
main

**Reproduces locally?:**
Didn't try

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.xpack.esql.expression.function.scalar.nulls.CoalesceTests&tests.test=classMethod
**Failure excerpt:**
```
java.lang.Exception: Suite timeout exceeded (>= 2400000 msec).

  at __randomizedtesting.SeedInfo.seed([546AEE28130887AC]:0)

```
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/AbstractFunctionTestCase.java
for (DataType arg : sig.getKey()) {
                b.append(arg.typeName()).append(" | ");
            }
            b.append(sig.getValue().typeName());
            table.add(b.toString());
        }
        Collections.sort(table);
        String rendered = """
            [%header.monospaced.styled,format=dsv,separator=|]
            |===
            """ + header + "\n" + table.stream().collect(Collectors.joining("\n")) + "\n|===\n";
        LogManager.getLogger(getTestClass()).info("Writing function types:\n{}", rendered);
        writeToTempDir("types", rendered, "asciidoc");
    }
    private static FunctionDefinition definition() {
        String name = functionName();
        EsqlFunctionRegistry registry = new EsqlFunctionRegistry();
        if (registry.functionExists(name)) {
            return registry.resolveFunction(name);
        }
        return null;
    }
    private static String functionName() {
        return StringUtils.camelCaseToUnderscore(getTestClass().getSimpleName().replace("Tests", "")).toLowerCase(Locale.ROOT);
    }
    /**
     * Write some text to a tempdir so we can copy it to the docs later.
     * <p>
     *     We need to write to a tempdir instead of the docs because the tests
     *     don't have write permission to the docs.