I got an unexpected internal NPE when playing with this script.

```
POST _scripts/painless/_execute
{
  "script": {
    "source": """
    return /[^\w]+/.split('abc   def higkln').toArray(String[]::new)
    """
  }
}
```
```
{
  "error" : {
    "root_cause" : [
      {
        "type" : "script_exception",
        "reason" : "compile error",
        "script_stack" : [ ],
        "script" : "\n    return /[^\\w]+/.split('abc   def higkln').toArray(String[]::new)\n    ",
        "lang" : "painless"
      }
    ],
    "type" : "script_exception",
    "reason" : "compile error",
    "script_stack" : [ ],
    "script" : "\n    return /[^\\w]+/.split('abc   def higkln').toArray(String[]::new)\n    ",
    "lang" : "painless",
    "caused_by" : {
      "type" : "null_pointer_exception",
      "reason" : "Cannot read field \"annotations\" because the return value of \"org.elasticsearch.painless.lookup.PainlessLookup.lookupPainlessClass(java.lang.Class)\" is null"
    }
  },
  "status" : 400
}

```
modules/lang-painless/src/main/java/org/elasticsearch/painless/phase/DefaultSemanticAnalysisPhase.java
new IllegalArgumentException("Argument(s) cannot be of [void] type when calling method [" + methodName + "].")
                    );
                }
            }
            TargetType targetType = userCallNode.isNullSafe() ? null : semanticScope.getDecoration(userCallNode, TargetType.class);
            valueType = targetType == null || semanticScope.getCondition(userCallNode, Explicit.class)
                ? def.class
                : targetType.targetType();
            semanticScope.setCondition(userCallNode, DynamicInvocation.class);
        } else {
            Objects.requireNonNull(method);
            semanticScope.getScriptScope().markNonDeterministic(method.annotations().containsKey(NonDeterministicAnnotation.class));
            for (int argument = 0; argument < userArgumentsSize; ++argument) {
                AExpression userArgumentNode = userArgumentNodes.get(argument);
                semanticScope.setCondition(userArgumentNode, Read.class);
                semanticScope.putDecoration(userArgumentNode, new TargetType(method.typeParameters().get(argument)));
                semanticScope.setCondition(userArgumentNode, Internal.class);
                checkedVisit(userArgumentNode, semanticScope);
                decorateWithCast(userArgumentNode, semanticScope);
            }
            semanticScope.putDecoration(userCallNode, new StandardPainlessMethod(method));
            valueType = method.returnType();
        }
        if (userCallNode.isNullSafe() && valueType.isPrimitive()) {
            throw new IllegalArgumentException("Result of null safe operator must be nullable");
        }
        semanticScope.putDecoration(userCallNode, new ValueType(valueType));
    }
}