Remove unsued code.

[Shylock-Hg]

What type of PR is this?

• bug
• feature
• enhancement

What problem(s) does this PR solve?

Issue(s) number:

Description:

How do you solve it?

Special notes for your reviewer, ex. impact of this fix, design document, etc:

Checklist:

Tests:

• Unit test(positive and negative cases)
• Function test
• Performance test
• N/A

Affects:

• Documentation affected (Please add the label if documentation needs to be modified.)
• Incompatibility (If it breaks the compatibility, please describe it and add the label.）
• If it's needed to cherry-pick (If cherry-pick to some branches is required, please label the destination version(s).)
• Performance impacted: Consumes more CPU/Memory

Release notes:

Please confirm whether to be reflected in release notes and how to describe:

ex. Fixed the bug .....

[codecov-commenter]

Codecov Report

Merging #4083 (64f35c9) into master (07cbbac) will decrease coverage by 0.05%.
The diff coverage is 38.09%.

@@            Coverage Diff             @@
##           master    #4083      +/-   ##
==========================================
- Coverage   85.08%   85.03%   -0.06%     
==========================================
  Files        1324     1324              
  Lines      131911   131926      +15     
==========================================
- Hits       112236   112178      -58     
- Misses      19675    19748      +73     

Impacted Files	Coverage Δ
src/graph/executor/admin/SpaceExecutor.cpp	76.99% <ø> (-0.22%)	⬇️
src/meta/test/BalancerTest.cpp	94.70% <ø> (-1.41%)	⬇️
src/parser/test/ParserTest.cpp	100.00% <ø> (ø)
src/meta/processors/job/ZoneBalanceJobExecutor.cpp	74.77% <14.28%> (-13.82%)	⬇️
src/meta/processors/zone/AddHostsProcessor.cpp	72.41% <35.00%> (-19.70%)	⬇️
src/meta/processors/zone/DropHostsProcessor.cpp	70.67% <40.00%> (-2.50%)	⬇️
src/clients/meta/MetaClient.cpp	76.41% <50.00%> (-0.64%)	⬇️
src/graph/validator/GroupByValidator.cpp	95.37% <100.00%> (+0.08%)	⬆️
src/meta/processors/parts/GetSpaceProcessor.cpp	61.29% <0.00%> (-19.36%)	⬇️
... and 47 more

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