Add expression index in multi-schema change panic

[tangenta]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

drop table if exists t;
create table t (a int, b int);
insert into t values (1, 2), (2, 1);
alter table t add column c int default 10, add index idx1((a + b)), add unique index idx2((a + b));

2. What did you expect to see? (Required)

ERROR 1062 (23000): Duplicate entry '3' for key 't.idx2'

3. What did you see instead (Required)

ERROR 1105 (HY000): When the state is JobStateRollbackDone or JobStateCancelled, historyJob.Error should never be nil

Log output

[2022/06/15 10:27:01.531 +08:00] [ERROR] [misc.go:109] ["panic in the recoverable goroutine"] [label=ddl-worker] [funcInfo="worker 2, tp reorg runDDLJob"] [r="\"invalid memory address or nil pointer dereference\""] [stack="github.com/pingcap/tidb/util.Recover
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/util/misc.go:113
runtime.gopanic
  /opt/homebrew/Cellar/go/1.18.1/libexec/src/runtime/panic.go:844
runtime.panicmem
  /opt/homebrew/Cellar/go/1.18.1/libexec/src/runtime/panic.go:220
runtime.sigpanic
  /opt/homebrew/Cellar/go/1.18.1/libexec/src/runtime/signal_unix.go:818
github.com/pingcap/tidb/parser/model.FindColumnInfo
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/parser/model/model.go:285
github.com/pingcap/tidb/ddl.getPrimaryKey
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/ddl_api.go:1662
github.com/pingcap/tidb/ddl.checkInvisibleIndexOnPK
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/ddl_api.go:1631
github.com/pingcap/tidb/ddl.(*worker).onCreateIndex
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/index.go:542
github.com/pingcap/tidb/ddl.(*worker).runDDLJob
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/ddl_worker.go:893
github.com/pingcap/tidb/ddl.onMultiSchemaChange
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/multi_schema_change.go:94
github.com/pingcap/tidb/ddl.(*worker).runDDLJob
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/ddl_worker.go:959
github.com/pingcap/tidb/ddl.(*worker).handleDDLJobQueue.func1
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/ddl_worker.go:645
github.com/pingcap/tidb/kv.RunInNewTxn
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/kv/txn.go:127
github.com/pingcap/tidb/ddl.(*worker).handleDDLJobQueue
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/ddl_worker.go:598
github.com/pingcap/tidb/ddl.(*worker).start
  /Users/tangenta/gopath/src/github.com/pingcap/tidb/ddl/ddl_worker.go:211"]

4. What is your TiDB version? (Required)

a75690f