util/size: define some constants for size

[tangenta]

What problem does this PR solve?

Problem Summary:

We can extract the size constants to a dedicated package for reuse.

What is changed and how it works?

Check List

Tests

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

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• hawkingrei
• xhebox

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[hawkingrei]

Have some problem about lint. Please fix it.

[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/acc4d32b28d9378a905c76f1d75476a78b04c9c5

[hawkingrei]

/merge

[xhebox]

/merge

[ti-chi-bot]

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

Commit hash: 043ab16

[ti-chi-bot]

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

Commit hash: 043ab16

[sre-bot]

TiDB MergeCI notify

🔴 Bad News! [2] CI still failing after this pr merged.
These failed integration tests don't seem to be introduced by the current PR.

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci-tidb/integration-common-test	🔴 failed 2, success 15, total 17	15 min	Existing failure
idc-jenkins-ci-tidb/common-test	🔴 failed 2, success 9, total 11	12 min	Existing failure
idc-jenkins-ci/integration-cdc-test	🟢 all 36 tests passed	31 min	Existing passed
idc-jenkins-ci-tidb/integration-ddl-test	🟢 all 6 tests passed	5 min 51 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	5 min 33 sec	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	10 min	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	7 min 1 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	3 min 53 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	3 min 13 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed