fix bug that mpp_fail test cost too much time / Fix test clustered index test cases (#1591)

[ti-srebot]

cherry-pick #1591 to release-5.0
You can switch your code base to this Pull Request by using git-extras:

# In tics repo:
git pr https://github.com/pingcap/tics/pull/1600

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tics.git pr/1600:release-5.0-891466e91f1d

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What problem does this PR solve?

Issue Number: close #xxx

Problem Summary:

After pingcap/tidb#23056, fullstack test mpp_fail takes too much time(more than 10 minutes), which is expected.

What is changed and how it works?

Proposal: xxx

What's Changed:

How it Works:

The root cause is after pingcap/tidb#23056, TiDB will send kill command to kill all the mpp tasks for a specified query, and currently implementation of cancelling a mpp task will call writeErrToAllTunnel to write error message to other mpp tasks, since all the mpp tasks are canceled at the same time, writeErrToAllTunnel might hangs for a little time(write error message until tunnel is timeout), so the test execution time is much more than expected. In this pr, when canceling a mpp task, it just call closeAllTunnel to close the tunnel, which only write error message to other mpp task if the tunnel is already connected.

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• Need to cherry-pick to the release branch

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression
  • Consumes more CPU
  • Consumes more MEM
• Breaking backward compatibility

Release note

• No release note

[JaySon-Huang]

/run-all-tests

[JaySon-Huang]

LGTM