*: add two black DML cases for auto recovery; fix panic when commit DML txn failed (#312)

[sre-bot]

cherry-pick #312 to release-1.0

---

What problem does this PR solve?

• do not automatically recovery task for Duplicate entry and Data too long for column error
• fix panic when committing DML txn failed

panic: runtime error: index out of range

goroutine 213 [running]:
github.com/pingcap/dm/syncer.(*Syncer).sync.func3(0xc008504eb0, 0xc008504e37)
	/Users/zhangxc/gopath/src/github.com/csuzhangxc/dm/syncer/syncer.go:953 +0x91e
github.com/pingcap/dm/syncer.(*Syncer).sync(0xc00019d400, 0xc008504f88, 0xc000044998, 0x3, 0xc000448be0, 0xc000353d40)
	/Users/zhangxc/gopath/src/github.com/csuzhangxc/dm/syncer/syncer.go:993 +0x483
github.com/pingcap/dm/syncer.(*Syncer).Run.func2(0x24e1c00, 0xc00004ae40, 0xc00019d400, 0xe, 0xc000044998, 0x3)
	/Users/zhangxc/gopath/src/github.com/csuzhangxc/dm/syncer/syncer.go:1062 +0xdf
created by github.com/pingcap/dm/syncer.(*Syncer).Run
	/Users/zhangxc/gopath/src/github.com/csuzhangxc/dm/syncer/syncer.go:1059 +0x4ea

What is changed and how it works?

• add two black DML cases for auto recovery
• return len(queries)-1 when committing failed

Check List

Tests

• Unit test

Related changes

• Need to cherry-pick to the release branch
• Need to be included in the release note

[amyangfei]

LGTM

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-1.0@d65b307). Click here to learn what that means.
The diff coverage is 85.7142%.

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[WangXiangUSTC]

LGTM