executor: kill tableReader for each connection correctly (#18277)

[ti-srebot]

cherry-pick #18277 to release-3.0

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What problem does this PR solve?

Issue Number: close a part of #18057

Problem Summary:
The tableReader in the coprocessor may retry many times to read regions, druing which, it cannot be aware of the cancelation from client. It may take much of memory for a long time.

What is changed and how it works?

Proposal: detect Killed to stop the goroutine.

What's Changed: should not use CompareAndSwap to change the Killed before Close(), because many runninig goroutines should detect the Killed.

How it Works: the TableReader the detect the killed in every loop.
The query may not exit quickly, because the query do some close work.

Check List

Tests

• Integration test
• Manual test (add detailed scripts or steps below)
  test on mocktikv:

step1. explain analyze select * from lineitem;
step2. kill tidb sessionID on another client;
to see the connection is cancelled.

similarly test on TiFlash is ok.

Release note

• To speed up canceling a query

[ti-srebot]

/run-all-tests

[ti-srebot]

@fzhedu please accept the invitation then you can push to the cherry-pick pull requests.
https://github.com/ti-srebot/tidb/invitations

[fzhedu]

/rebuild

[SunRunAway]

LGTM

[qw4990]

LGTM

[qw4990]

/merge

[ti-srebot]

Sorry @qw4990, you don't have permission to trigger auto merge event on this branch.

[qw4990]

/merge

[ti-srebot]

/run-all-tests