*: Added server_debug to have a better experience when using a debugger

[mjonss]

What problem does this PR solve?

Added build option for debug build of tidb-server

Problem Summary:
When using a debugger as delve, it is hard to follow the execution and inspect some areas due to optimized build, this makes it easier to build a debug version of the server binary to run in a debugger.

What is changed and how it works?

What's Changed: Added server_debug make target

How it Works: make server_debug which will create bin/tidb-server-debug

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

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• bb7133
• morgo

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[bb7133]

PTAL @blacktear23

[blacktear23]

@bb7133 LGTM

[morgo]

/merge

[ti-chi-bot]

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

Commit hash: 5223d94