issue: 3777348 Improvements for TCP flow unnecessary cache access.

[AlexanderGrissik]

Description

This PR is based on PR 110 (issue: 3777348 Move socket statistics to a global storage) This PR starts from commit: issue: 3777348 Removing m_flow_tag_enabled check

What

Avoid unnecessary cache lines access. Descriptions of each change are in the commits. Recommend to review by commits.

Why ?

Improve performance.

Change type

What kind of change does this PR introduce?

• [ ] Bugfix
• [X] Feature
• [ ] Code style update
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] CI related changes
• [ ] Documentation content changes
• [ ] Tests
• [ ] Other

Check list

• [X] Code follows the style de facto guidelines of this project
• [X] Comments have been inserted in hard to understand places
• [X] Documentation has been updated (if necessary)
• [ ] Test has been added (if possible)