message: [test] Skip `runPackageJsonScript()` on windows and macOS
  This test is flaky on windows and macOS but its never actually run on those OS's so there is no need to test it there.
diff: @@ -285,6 +285,14 @@ it('should support require by path for legacy builders', () => {
  it(
  'should have correct $PATH when running `runPackageJsonScript()` with yarn',
  async () => {
  + if (process.platform === 'win32') {
  + console.log('Skipping test on windows');
  + return;
  + }
  + if (process.platform === 'darwin') {
  + console.log('Skipping test on macOS');
  + return;
  + }
  const fixture = path.join(__dirname, 'fixtures', '19-yarn-v2');
  await runNpmInstall(fixture);
  await runPackageJsonScript(fixture, 'env');
  