Wrong/misleading error for "extra" close token (`]` or `}`) when at root level

[cowtowncoder]

(note: found as part of work on FasterXML/jackson-databind#4902 to enable "fail on extra tokens" DeserializationFeature).

So: odd failures seen for tests:

[ERROR]   TestSubtypesExternalPropertyMissingProperty.testDeserializationNull:141->checkOrangeBoxNull:232 » 
  JsonParse Unexpected close marker '}': expected ']' (for root starting
   at [Source: (String)"{"type":"orange","fruit":null}}"; line: 1, column: 0])

which is due to ReaderBasedJsonParser (and others), on:

    private void _closeScope(int i) throws IOException {
        if (i == INT_RBRACKET) {
            _updateLocation();
            if (!_parsingContext.inArray()) {
                _reportMismatchedEndMarker(i, '}');
            }
            _parsingContext = _parsingContext.clearAndGetParent();
            _updateToken(JsonToken.END_ARRAY);
        }
        ...
   }

in which check is assuming there always IS a start marker -- but fails to consider case where there is no open scope. It should.

This needs to be checked against all 4 backends