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
throw userNumericNode.createError(new IllegalArgumentException("Invalid long constant [" + numeric + "]."));
            }
        } else {
            try {
                TargetType targetType = semanticScope.getDecoration(userNumericNode, TargetType.class);
                Class<?> sort = targetType == null ? int.class : targetType.targetType();
                int integer = Integer.parseInt(numeric, radix);
                if (sort == byte.class && integer >= Byte.MIN_VALUE && integer <= Byte.MAX_VALUE) {
                    constant = (byte) integer;
                    valueType = byte.class;
                } else if (sort == char.class && integer >= Character.MIN_VALUE && integer <= Character.MAX_VALUE) {
                    constant = (char) integer;
                    valueType = char.class;
                } else if (sort == short.class && integer >= Short.MIN_VALUE && integer <= Short.MAX_VALUE) {
                    constant = (short) integer;
                    valueType = short.class;
                } else {
                    constant = integer;
                    valueType = int.class;
                }
            } catch (NumberFormatException exception) {
                try {
                    
                    Long.parseLong(numeric, radix);
                    throw userNumericNode.createError(
                        new IllegalArgumentException(
                            "Invalid int constant [" + numeric + "]. If you want a long constant then change it to [" + numeric + "L]."
                        )
                    );
                } catch (NumberFormatException longNoGood) {