fix: remove process listeners after stopping the server

[snitin315]

• This is a bugfix
• This is a feature
• This is a code refactor
• This is a test update
• This is a docs update
• This is a metadata update

For Bugs and Features; did you add new tests?

No

Motivation / Use-Case

fix memory leak warnings in e2e tests.

Breaking Changes

None

Additional Info

No

[codecov]

Codecov Report

Merging #4013 (3896404) into master (270da15) will increase coverage by 0.12%.
The diff coverage is 95.83%.

@@            Coverage Diff             @@
##           master    #4013      +/-   ##
==========================================
+ Coverage   92.62%   92.74%   +0.12%     
==========================================
  Files          14       14              
  Lines        1410     1420      +10     
  Branches      519      524       +5     
==========================================
+ Hits         1306     1317      +11     
+ Misses         96       95       -1     
  Partials        8        8              

Impacted Files	Coverage Δ
lib/Server.js	94.16% <95.83%> (+0.14%)	⬆️

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[alexander-akait]

We should not remove all of them just only our, move our close function above the file and use removeListener

[snitin315]

above where?

[alexander-akait]

Somewhere here https://github.com/webpack/webpack-dev-server/blob/master/lib/Server.js#L17, like

if (needForceShutdown) {
            exitProcess();
          }

          this.logger.info(
            "Gracefully shutting down. To force exit, press ^C again. Please wait..."
          );

          needForceShutdown = true;

          this.stopCallback(() => {
            if (typeof this.compiler.close === "function") {
              this.compiler.close(exitProcess);
            } else {
              exitProcess();
            }
});

from https://github.com/webpack/webpack-dev-server/blob/master/lib/Server.js#L1177

[alexander-akait]

I.e. just move it in function above the Server class and remove this listener in close