Avoid allocating slice for finding Process

[tedyu]

For checkProcesses(), we obtain slice of Processes via allProcesses() and only use one of them where Pid matches.

allProcesses() is not exported and not used elsewhere in service.go.

This PR replaces allProcesses() by finding Process given Pid inside checkProcesses().

[theopenlab-ci]

Build succeeded.

• containerd-build-arm64 : SUCCESS in 7m 52s (non-voting)

[codecov-io]

Codecov Report

Merging #4058 into master will decrease coverage by 3.35%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4058      +/-   ##
==========================================
- Coverage   45.89%   42.53%   -3.36%     
==========================================
  Files         117      130      +13     
  Lines       11891    14828    +2937     
==========================================
+ Hits         5457     6307     +850     
- Misses       5516     7602    +2086     
- Partials      918      919       +1

Flag	Coverage Δ
#linux	45.89% <ø> (ø)	⬆️
#windows	38.22% <ø> (?)

Impacted Files	Coverage Δ
archive/tar_opts.go	58.82% <0%> (-12.61%)	⬇️
snapshots/native/native.go	42.42% <0%> (-10.27%)	⬇️
archive/tar.go	48.58% <0%> (-8.63%)	⬇️
cio/io.go	46.47% <0%> (-8.53%)	⬇️
metadata/snapshot.go	47.57% <0%> (-7.2%)	⬇️
metadata/containers.go	49.84% <0%> (-6.26%)	⬇️
content/local/writer.go	58.65% <0%> (-5.55%)	⬇️
content/local/store.go	49.52% <0%> (-5.29%)	⬇️
metadata/images.go	57.41% <0%> (-4.97%)	⬇️
archive/compression/compression.go	58.69% <0%> (-4.7%)	⬇️
... and 74 more

---

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[Zyqsempai]

Please sign your commit git commit -s

[AkihiroSuda]

What's the purpose of this PR?

[tedyu]

@AkihiroSuda
allProcesses() composes a slice where only one element is used.
This is wasteful.

This PR does cleanup.

[theopenlab-ci]

Build succeeded.

• containerd-build-arm64 : SUCCESS in 8m 07s (non-voting)

[theopenlab-ci]

Build succeeded.

• containerd-build-arm64 : SUCCESS in 7m 47s (non-voting)

[theopenlab-ci]

Build succeeded.

• containerd-build-arm64 : SUCCESS in 7m 22s (non-voting)

[crosbymichael]

should be good to rebase now

[tedyu]

@crosbymichael
Rebase has been done.

[theopenlab-ci]

Build succeeded.

• containerd-build-arm64 : SUCCESS in 7m 41s (non-voting)

[estesp]

LGTM

[crosbymichael]

LGTM