pkg/tso: add go trace information for tso allocation

[tiancaiamao]

What problem does this PR solve?

Issue Number: Close #4399

What is changed and how does it work?

Add some trace annotation so 'go tool trace' can show the execution tracing information.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

curl 'http://127.0.0.1:2379/pd/api/v1/debug/pprof/trace?seconds=3' > trace.out
go tool trace -http=:6060 trace.out

And observe the trace result on the web.

• No code

Code changes

• Has the configuration change
• Has HTTP API interfaces changed (Don't forget to add the declarative for the new API)
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

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

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lhy1024

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[ti-chi-bot]

This cherry pick PR is for a release branch and has not yet been approved by release team.
Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-chi-bot]

Hi @tiancaiamao. Thanks for your PR.

I'm waiting for a tikv member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[lhy1024]

Thanks! but ci failed

[lhy1024]

how about "tso"？

[tiancaiamao]

Oh, I meant to provide a hotfix for a customer to debug their issues.
This one should have been made it a draft pr, it's not based on the master branch.
@lhy1024

[tiancaiamao]

Close this one in favor of #6884