Automated cherry pick of #1485: fix(scheduler): sync instance info memory leak

[erda-bot]

Cherry pick of #1485 on release/1.2.

Squashed commit message:

commit 5ec04d29bcd6c7176c0b091c5238af1f670c92bd
Author: Muzry <muzrry@gmail.com>
Date:   Wed Aug 18 10:19:21 2021 +0800

    fix(scheduler): sync instance info memory leak (#1485)

---

What type of this PR

Add one of the following kinds:
/kind bug

What this PR does / why we need it:

• fix(scheduler): sync instance info memory leak

Which issue(s) this PR fixes:

• Fixes #your-issue_number
• [Erda Cloud Issue Link](paste your link here)

Specified Reviewers:

/assign @luobily @sixther-dc

ChangeLog

Language	Changelog
🇺🇸 English	fix(scheduler): sync instance info memory leak
🇨🇳 中文	修复获取实例列表内存泄漏的问题

Need cherry-pick to release versions?

Add comment like /cherry-pick release/1.0 when this PR is merged.

For details on the cherry pick process, see the cherry pick requests section under CONTRIBUTING.md.

[codecov]

Codecov Report

Merging #1493 (5ec04d2) into release/1.2 (2c863de) will increase coverage by 0.00%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##           release/1.2    #1493   +/-   ##
============================================
  Coverage        12.07%   12.07%           
============================================
  Files              983      983           
  Lines           102557   102557           
============================================
+ Hits             12384    12387    +3     
+ Misses           89064    89063    -1     
+ Partials          1109     1107    -2     

Impacted Files	Coverage Δ
modules/scheduler/executor/plugins/k8s/k8s.go	1.12% <ø> (ø)
pkg/mock/mock.go	29.54% <0.00%> (+3.40%)	⬆️

[sfwn]

/approve