test: stability (#4150)

Author: alexander-akait

test/serve/basic/__snapshots__/serve-basic.test.js.snap.devServer4.webpack5

@@ -67,8 +67,6 @@ exports[`basic serve usage should throw error when same ports in multicompiler:
     at stack"
 `;
 
-exports[`basic serve usage should throw error when same ports in multicompiler: stdout 1`] = `""`;
-
 exports[`basic serve usage should work and log warning on the 'watch' option in a configuration: stderr 1`] = `
 "[webpack-cli] No need to use the 'serve' command together with '{ watch: true | false }' or '--watch'/'--no-watch' configuration, it does not make sense.
 <i> [webpack-dev-server] Project is running at:

test/serve/basic/__snapshots__/serve-basic.test.js.snap.devServer5.webpack5

@@ -67,8 +67,6 @@ exports[`basic serve usage should throw error when same ports in multicompiler:
     at stack"
 `;
 
-exports[`basic serve usage should throw error when same ports in multicompiler: stdout 1`] = `""`;
-
 exports[`basic serve usage should work and log warning on the 'watch' option in a configuration: stderr 1`] = `
 "[webpack-cli] No need to use the 'serve' command together with '{ watch: true | false }' or '--watch'/'--no-watch' configuration, it does not make sense.
 <i> [webpack-dev-server] Project is running at:

test/serve/basic/serve-basic.test.js

@@ -481,13 +481,14 @@ describe("basic serve usage", () => {
   });
 
   it("should throw error when same ports in multicompiler", async () => {
-    const { stderr, stdout } = await runWatch(__dirname, [
+    const { stderr } = await runWatch(__dirname, [
       "serve",
       "--config",
       "same-ports-dev-server.config.js",
     ]);
 
     expect(normalizeStderr(stderr)).toMatchSnapshot("stderr");
-    expect(normalizeStdout(stdout)).toMatchSnapshot("stdout");
+    // Due to racing logic, first dev server can be started and compiled, but then the second always fails
+    // expect(normalizeStdout(stdout)).toMatchSnapshot("stdout");
   });
 });