infoschema, domain, ddl: fix upper cased charset names

[bb7133]

What problem does this PR solve?

This version aims to deal with upper-cased charset name in TableInfo stored by previous versions of TiDB.

TiDB always supposes that all charsets / collations are lower-cased and try to convert them if they're not. However, the convert is missed in some scenarios, some upper-cased charsets / collations are kept and stored, leading to some potential issues:

mysql> create table t1(a varchar(20)) default charset=utf8;
Query OK, 0 rows affected (0.03 sec)
mysql> insert into t1 values ('特克斯和凯科斯群岛');
Query OK, 1 row affected (0.01 sec)

mysql> create table t2(a varchar(20)) default charset=UTF8;
Query OK, 0 rows affected (0.03 sec)
mysql> insert into t2 values ('特克斯和凯科斯群岛');
ERROR 1406 (22001): Data too long for column 'a' at row 1

mysql> select version();
+------------------------------------------+
| version()                                |
+------------------------------------------+
| 5.7.25-TiDB-v3.0.0-beta.1-104-g0a9569af4 |
+------------------------------------------+
1 row in set (0.00 sec)

What is changed and how it works?

With the help of pingcap/parser#301, a new TableInfoVersion3 is added as CurrLatestTableInfoVersion. All tables with version prior to TableInfoVersion3 will do the charset / collation name convert when loaded.

Also, pingcap/parser#301 validates all charset / collation names and convert them to lower-case in parser.

Check List

Tests

• Integration test

Code changes

• Has exported function/method change

Side effects

• (Potentially) Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch

[mahjonp]

/rebuild

[zhouqiang-cl]

/rebuild

[zhouqiang-cl]

/rebuild

[mahjonp]

/rebuild

[winkyao]

LGTM

[codecov]

Codecov Report

Merging #10272 into master will increase coverage by 0.0154%.
The diff coverage is 100%.

@@               Coverage Diff                @@
##             master     #10272        +/-   ##
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+ Coverage   77.6568%   77.6723%   +0.0154%     
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  Files           411        411                
  Lines         85431      85441        +10     
================================================
+ Hits          66343      66364        +21     
+ Misses        14124      14119         -5     
+ Partials       4964       4958         -6

[lonng]

LGTM

[crazycs520]

LGTM

[crazycs520]

/run-all-tests

[bb7133]

/run-unit-test