[IMP] tests: refactor _wait_remaining_requests

After a browser_js, http requests threads are joined. If one of them
doesn't finish gracefully, a dumpstacks occurs.
As the dumpstacks call is in a loop, it can quickly polute logs. Even
more, a the dumptack may include threads that were not yet processed and
that will be joined in a future loop.

With this commit, dumpstacks will be called once and for all at the end
of the method, if at least one thread is remaining.

Furthermore, before this commit a sleep of 0.5 sec occured at most ten
times for each thread before considering it as lost. It means that each
thread is benefiting of the cumumulated time of the previous ones.
That's not fair.

With this commit, a default timeout of 10 sec is used for all threads.
The original warning is kept for each remaining request.

odoo/tests/common.py

@@ -929,26 +929,26 @@ class HttpCase(TransactionCase):
             return self.opener.post(url, data=data, files=files, timeout=timeout, headers=headers)
         return self.opener.get(url, timeout=timeout, headers=headers)
 
-    def _wait_remaining_requests(self):
-        t0 = int(time.time())
-        for thread in threading.enumerate():
-            if thread.name.startswith('odoo.service.http.request.'):
-                join_retry_count = 10
-                while thread.isAlive():
-                    # Need a busyloop here as thread.join() masks signals
-                    # and would prevent the forced shutdown.
-                    thread.join(0.05)
-                    join_retry_count -= 1
-                    if join_retry_count < 0:
-                        self._logger.warning("Stop waiting for thread %s handling request for url %s",
-                                        thread.name, getattr(thread, 'url', '<UNKNOWN>'))
-                        break
-                    time.sleep(0.5)
-                    t1 = int(time.time())
-                    if t0 != t1:
-                        self._logger.info('remaining requests')
-                        odoo.tools.misc.dumpstacks()
-                        t0 = t1
+    def _wait_remaining_requests(self, timeout=10):
+
+        def get_http_request_threads():
+            return [t for t in threading.enumerate() if t.name.startswith('odoo.service.http.request.')]
+
+        start_time = time.time()
+        request_threads = get_http_request_threads()
+        self._logger.info('waiting for threads: %s', request_threads)
+
+        for thread in request_threads:
+            thread.join(timeout - (time.time() - start_time))
+
+        request_threads = get_http_request_threads()
+        for thread in request_threads:
+            self._logger.warning("Stop waiting for thread %s handling request for url %s",
+                                    thread.name, getattr(thread, 'url', '<UNKNOWN>'))
+
+        if request_threads:
+            self._logger.info('remaining requests')
+            odoo.tools.misc.dumpstacks()
 
     def authenticate(self, user, password):
         # stay non-authenticated