[FIX] tests: detect coverage and adjust timeout

When computing coverage, the tests are slowed down and the timeout is
often exceeded.

With this commit, HttpCase headless Chrome tests timeout is increased if
coverage is detected.

odoo/tests/common.py

@@ -857,6 +857,9 @@ class HttpCase(TransactionCase):
 
         If neither are done before timeout test fails.
         """
+        # increase timeout if coverage is running
+        if any(f.filename.endswith('/coverage/execfile.py') for f in inspect.stack()  if f.filename):
+            timeout = timeout * 1.5
         self.start_browser(self._logger)
 
         try: