There are two issues here.
1. The test fails because it expects null, but get undefined and not because of the thrown exceptions.
2. Chrome does throw an exception every time you access onclick.

So the test case fails due to issue 1 right now (and once this is fixed, it will fail due to  issue 2 ).

Here is a test for the both of the issues (I just eliminated the early bail out due to the first exception) -
data:text/html,
<script>
window.addEventListener(
 "load",
 function ()
 {
  var errors = 0;
  window.onerror =
   function ()
   {
    errors++;
   };
  var e = document.body;
  e.setAttribute("onclick", "window.open(");
  console.log(e.onclick === null);
  console.log(e.onclick === null);
  console.log(errors);
 });
</script>

Or you can change console.log(errors) to console.log(errors === 1);
The expected result should be -
true
true
true

The actual result -
false
false
false

phistuck: thanks for the analysis!  Filed  issue 613671  for the null/undefined issue.

Relevant spec:
https://html.spec.whatwg.org/multipage/webappapis.html#event-handler-content-attributes
https://html.spec.whatwg.org/multipage/webappapis.html#internal-raw-uncompiled-handler

Simple demo page: http://output.jsbin.com/vecoto

Browsers tested:
Chrome 52.0.2739.0 Linux: fail
Firefox 46.0 Linux: pass
Safari 9.1 Mac: fail
Edge 13.10586 Win10: pass
IE 11 Win10: pass

haraken@ thoughts?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2fb386fd03fc84f7ba3a72417bc2345ad6f308c4

commit 2fb386fd03fc84f7ba3a72417bc2345ad6f308c4
Author: yukishiino <yukishiino@chromium.org>
Date: Fri Jul 29 15:21:27 2016

binding: Compiles event handlers only once if not compilable.

Blink no longer compiles a script for an event handler twice
or more if the script is not compilable.

BUG= 597900 

Review-Url: https://codereview.chromium.org/2190553003
Cr-Commit-Position: refs/heads/master@{#408638}

[modify] https://crrev.com/2fb386fd03fc84f7ba3a72417bc2345ad6f308c4/third_party/WebKit/LayoutTests/imported/wpt/html/webappapis/scripting/events/invalid-uncompiled-raw-handler-compiled-once-expected.txt
[modify] https://crrev.com/2fb386fd03fc84f7ba3a72417bc2345ad6f308c4/third_party/WebKit/Source/bindings/core/v8/V8AbstractEventListener.h
[modify] https://crrev.com/2fb386fd03fc84f7ba3a72417bc2345ad6f308c4/third_party/WebKit/Source/bindings/core/v8/V8LazyEventListener.cpp
[modify] https://crrev.com/2fb386fd03fc84f7ba3a72417bc2345ad6f308c4/third_party/WebKit/Source/bindings/core/v8/V8LazyEventListener.h