syncer, relay: avoid read duplicate event when retry binlog streamer

[glorv]

What problem does this PR solve?

avoiding read duplicate event in syncer and relay log.

What is changed and how it works?

• Relay
  • discard the events that already written when reset binlog reader in GTID mode
  • return an error ErrorMaybeDuplicateEvent when the relay log is not complete(not end with RotateEvent).
• Syncer
  • recording the read event index and drop the first n events when reset streamer in GTID mode.
  • drop the first n events when binlog streamer returns the error ErrorMaybeDuplicateEvent

Check List

Tests

• Integration test

Code changes

Side effects

Related changes

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

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Ehco1996
• lance6716

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[lance6716]

seems an unstable test

[glorv]

seems an unstable test

fixed 😅

[lance6716]

weakly want to change the safe-mode behaviour

https://github.com/pingcap/dm/pull/2047/files#r699233692

[lance6716]

Suggested change

	cp $cur/conf/source1.yaml $WORK_DIR/source1.yaml
	dmctl_operate_source create $WORK_DIR/source1.yaml $SOURCE_ID1
	dmctl_operate_source create $cur/conf/source1.yaml $SOURCE_ID1

if we don't modify $cur/conf/source1.yaml

and for source2

[glorv]

@lance6716 I change the safe-mode logic to also directly skip N event, PTAL again.

[lance6716]

lgtm

[Ehco1996]

LGTM, please remember to fix lint error

[glorv]

/run-all-tests

[glorv]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 4b73e9c

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #2105.