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
method = semanticScope.getScriptScope()
                .getPainlessLookup()
                .lookupPainlessMethod(prefixStaticType.staticType(), true, methodName, userArgumentsSize);
            if (method == null) {
                throw userCallNode.createError(
                    new IllegalArgumentException(
                        "static method "
                            + "["
                            + prefixStaticType.getStaticCanonicalTypeName()
                            + ", "
                            + methodName
                            + "/"
                            + userArgumentsSize
                            + "] "
                            + "not found"
                    )
                );
            }
        } else {
            throw userCallNode.createError(new IllegalStateException("value required: instead found no value"));
        }
        Class<?> valueType;
        if (dynamic) {
            for (AExpression userArgumentNode : userArgumentNodes) {
                semanticScope.setCondition(userArgumentNode, Read.class);
                semanticScope.setCondition(userArgumentNode, Internal.class);
                checkedVisit(userArgumentNode, semanticScope);
                Class<?> argumentValueType = semanticScope.getDecoration(userArgumentNode, ValueType.class).valueType();
                if (argumentValueType == void.class) {
                    throw userCallNode.createError(