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
}
        EsqlFunctionRegistry.FunctionDescription description = EsqlFunctionRegistry.description(definition);
        List<EsqlFunctionRegistry.ArgSignature> args = description.args();
        List<Set<String>> typesFromSignature = new ArrayList<>();
        Set<String> returnFromSignature = new HashSet<>();
        for (int i = 0; i < args.size(); i++) {
            typesFromSignature.add(new HashSet<>());
        }
        for (Map.Entry<List<DataType>, DataType> entry : signatures.entrySet()) {
            List<DataType> types = entry.getKey();
            for (int i = 0; i < args.size() && i < types.size(); i++) {
                typesFromSignature.get(i).add(types.get(i).esType());
            }
            returnFromSignature.add(entry.getValue().esType());
        }
        for (int i = 0; i < args.size(); i++) {
            Set<String> annotationTypes = Arrays.stream(args.get(i).type()).collect(Collectors.toSet());
            if (annotationTypes.equals(Set.of("?"))) {
                continue; 
            }
            Set<String> signatureTypes = typesFromSignature.get(i);
            assertEquals(annotationTypes, signatureTypes);
        }
        Set<String> returnTypes = Arrays.stream(description.returnType()).collect(Collectors.toSet());
        if (returnTypes.equals(Set.of("?")) == false) { 
                                                        
            assertEquals(returnTypes, returnFromSignature);
        }
    }
    /**