kvclient: fix CRTs less than resolvedTs in puller

[zier-one]

What problem does this PR solve?

The resolvedTs may be reversed in the following cases：

1. There are RegionA and RegionB listened by TiCDC
2. RegionA and RegionB have merged to RegionAB, the checkpointTS is 5.
3. The RegionA failed message are sent to the error channel, the checkpointTS in RegionA failed message is 5.
4. And then, the RegionB failed message are sent to the error chennal, the checkpointTS in RegionB failed message is 5.
5. The error handler receives the RegionA failed message, rescan the ResionA, create a connection to listen RegionAB with 5 as startTs.
6. The connection was broken for some reason, the checkpointTs is 10.
7. And then, the ResionB failed message are received by The error handler, the handler rescan the RegionB, create a connection to listen RegionAB with 5 as startTs.

In steps 6 and 7, the ResolvedTS is regressed from 10 to 5.

What is changed and how it works?

In steps 7, use the checkpointTs record in range lock instead of which in failed message.

Check List

Tests

• Unit test
• Integration test

Release note

[zier-one]

/run-integration-tests

[MyonKeminta]

LGTM 👍

[ti-srebot]

@MyonKeminta,Thanks for your review. The bot only counts LGTMs from Reviewers and higher roles, but you're still welcome to leave your comments.See the corresponding SIG page for more information. Related SIG: tools(slack).

[zier-one]

/run-integration-tests

[codecov-commenter]

Codecov Report

Merging #927 into master will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             master       #927   +/-   ##
===========================================
  Coverage   33.8970%   33.8970%           
===========================================
  Files            99         99           
  Lines         12004      12004           
===========================================
  Hits           4069       4069           
  Misses         7534       7534           
  Partials        401        401           

[amyangfei]

LGTM

[overvenus]

/merge

[ti-srebot]

/run-all-tests

[zier-one]

/run-integration-tests

[ti-srebot]

@leoppro merge failed.