fix(launcher): make dumpio and pipe options work together (#4727)

Don't ignore stdout and stderr when using pipe for remote debugging and dumpio is true. In that case puppeteer process connects to the stdout/stderr streams of the child process and it will not hang.

test/fixtures/dumpio.js

@@ -2,6 +2,7 @@
   const [, , puppeteerRoot, options] = process.argv;
   const browser = await require(puppeteerRoot).launch(JSON.parse(options));
   const page = await browser.newPage();
+  await page.evaluate(() => console.error('message from dumpio'));
   await page.close();
   await browser.close();
 })();