Revert "[COOP] Access reporting. Fix the python server."

This reverts commit 9c96261a.

Reason for revert: This appears to have broken external/wpt/html/cross-origin-opener-policy/reporting/access-reporting/openee-accessed_openee-coop-ro.https.html

BUG: 1110254

Original change's description:
> [COOP] Access reporting. Fix the python server.
> 
> A python server is used has a communication channel in between documents
> from different browsing context group and potentially cross-origin.
> 
> There are two methods:
> - one for writing a message.
> - one for reading the message.
> 
> I initially supposed we won't need to store more than one message in the
> stash. It turns out there are tests doing two write in a row without any
> read in the middle. It was throwing an exception when this
> happened.
> 
> This patch makes the server to maintain a queue of messages instead. It
> doesn't throw errors anymore.
> 
> Bug: chromium:1109194
> Change-Id: I25f8dc2c2a032781a4527a0994e94e46f85e12c9
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2317865
> Reviewed-by: Pâris Meuleman <pmeuleman@chromium.org>
> Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#791901}

TBR=clamy@chromium.org,arthursonzogni@chromium.org,pmeuleman@chromium.org

Change-Id: I87ba2caa07f80f42aa549929ade392485b968d6f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1109194
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2320572Reviewed-by: Tim Schumann <tschumann@chromium.org>
Commit-Queue: Tim Schumann <tschumann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792184}

third_party/blink/web_tests/external/wpt/html/cross-origin-opener-policy/reporting/resources/dispatcher.py

@@ -9,17 +9,12 @@ def main(request, response):
         return b''
 
     uuid = request.GET[b'uuid']
-    stashed = request.server.stash.take(uuid)
-    if stashed is None:
-        stashed = []
 
     if request.method == u'POST':
-        stashed.append(request.body)
-        ret = b'done'
+        return request.server.stash.put(uuid, request.body)
     else:
-        if len(stashed) == 0:
-            ret = b'not ready'
+        body = request.server.stash.take(uuid)
+        if body is None:
+            return b'not ready'
         else:
-            ret = stashed.pop(0)
-    request.server.stash.put(uuid, stashed)
-    return ret;
+            return body