storage: support specifying normalizer in table comment

This change supports specifying normalizer in table comment.

* Example

```sql
CREATE TABLE Terms (
term VARCHAR(64) NOT NULL PRIMARY KEY
) COMMENT='default_tokenizer "TokenBigram", normalizer "NormalizerAuto"' DEFAULT CHARSET=utf8;
CREATE TABLE Memos (
id INT NOT NULL PRIMARY KEY,
content TEXT NOT NULL,
FULLTEXT INDEX (content) COMMENT 'table "Terms"'
) DEFAULT CHARSET=utf8;
INSERT INTO Memos VALUES (1, "1日の消費㌍は約2000㌔㌍");
SELECT * FROM Memos
WHERE MATCH (content) AGAINST ("+カロリー" IN BOOLEAN MODE);
id      content
1       1日の消費㌍は約2000㌔㌍
```