ddl, meta: allow increasing auto_random bits (#17423)

[tangenta]

Cherry-pick #17423 to release-4.0.

Release note

• The number of auto_random bits is allowed to increase by ALTER TABLE if possible.

[AilinKid]

LGTM

[tangenta]

/run-all-tests

[tangenta]

/run-unit-test

FAIL: db_test.go:977: testDBSuite2.TestAddPrimaryKey2

db_test.go:978:
    testAddIndex(c, s.store, s.lease, true,
        `create table test_add_index (c1 bigint, c2 bigint, c3 bigint, key(c1))
    			      partition by range (c3) (
    			      partition p0 values less than (3440),
    			      partition p1 values less than (61440),
    			      partition p2 values less than (122880),
    			      partition p3 values less than (204800),
    			      partition p4 values less than maxvalue)`, "primary")
/home/jenkins/agent/workspace/tidb_ghpr_unit_test/go/src/github.com/pingcap/tidb/util/testkit/testkit.go:190:
    tk.c.Assert(err, check.IsNil, check.Commentf("sql:%s, %v, error stack %v", sql, args, errors.ErrorStack(err)))
... value *errors.withStack = [domain:8027]Information schema is out of date: schema failed to update in 1 lease, please make sure TiDB can connect to TiKV ("[domain:8027]Information schema is out of date: schema failed to update in 1 lease, please make sure TiDB can connect to TiKV")

[djshow832]

LGTM

[tangenta]

/run-unit-test

TestT check-count 50 appears to have leaked

[bb7133]

/merge

[ti-srebot]

Your auto merge job has been accepted, waiting for:

• 18562

[ti-srebot]

/run-all-tests

[ti-srebot]

@tangenta merge failed.

[tangenta]

/run-integration-compatibility-test

level=warning msg="ping db failed