Fix console frame removal for password test site

In captured sites tests, we inject some javascript via WPR to check
for element readiness on the page.

After crrev.com/c/1884815, one password test (sign_up_fill/dreambox)
has a page with unrelated javascript errors which caused
frame.remove() to fail, so switching the frame destruction to use
document.body.removeChild(frame) instead.

Reran rest of test suite and verified passes for all password
tests this way.

Bug: 984664
Change-Id: I420427dc898affb62a0a200e59c72e470064dc92
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1895882
Auto-Submit: Ian Struiksma <ianstruiksma@google.com>
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711949}

chrome/test/data/web_page_replay_go_helper_scripts/automation_helper.js

@@ -84,7 +84,8 @@ const automation_helper = (function() {
       console.log(logDataArr.join(""));
     } finally {
       // Remove our temporary console iframe
-      frame.remove();
+      if(document.body.contains(frame))
+        document.body.removeChild(frame);
     }
     return isReady;
   };