perf: simplify logic, reduce extra loops and perf

[alexander-akait]

What kind of change does this PR introduce?

Avoid validation of our arguments from command line, i.e. when you have webpack --stats invalid

Did you add tests for your changes?

Update existing

If relevant, did you update the documentation?

No need

Summary

Webpack always validates provided configurations, when we have webpack --stats invalid, we just set stats to "invalid" value and now try to validate it, but I don't see any reasons to spend time on it, because when we pass it to webpack it will be validated again, so now we skip a one extra validation

We can't do it

Does this PR introduce a breaking change?

No

Other information

fixes #2626

[codecov]

Codecov Report

Merging #3767 (c682af9) into master (7235664) will decrease coverage by 0.02%.
The diff coverage is 96.36%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3767      +/-   ##
==========================================
- Coverage   91.64%   91.62%   -0.02%     
==========================================
  Files          22       22              
  Lines        1627     1624       -3     
  Branches      460      463       +3     
==========================================
- Hits         1491     1488       -3     
  Misses        136      136              

Impacted Files	Coverage Δ
packages/serve/src/index.ts	79.46% <0.00%> (ø)
packages/webpack-cli/src/webpack-cli.ts	93.02% <98.14%> (-0.02%)	⬇️

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7235664...c682af9. Read the comment docs.