[piexwasm] Fix tests.js startup crash on Linux Puppeteer

Linux Puppeteer startup in tests.js can sometimes crash. Fix this: add
chrome --no-sandbox arg to send to the Puppeteer browser startup.

Test: piex/tests.sh does not crash
No-try: true
Bug: 1132695
Change-Id: I27cccfdb0d49f46dcb07a343dfb474b0d9878331
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2442910Reviewed-by: Alex Danilo <adanilo@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813057}

ui/file_manager/image_loader/piex/tests.js

@@ -43,8 +43,14 @@ const puppeteer = require('puppeteer');
     console.log(puppeteer.defaultArgs());
   }
 
+  let args = [];
+  if (process.platform === 'linux') {
+    args = ['--no-sandbox'];
+  }
+
   const browser = await puppeteer.launch({
-    headless: !program.debug
+    headless: !program.debug,
+    args: [...args]
   });
 
   const page = await browser.newPage();