[BEAM-11045] Fix screendiff integration tests

1. Removed the server daemon process from screen diff tests. Replaced it
   with a lightweight daemon thread.
2. Upgraded chromedriver-binary version to 85 to match the newest chrome
   browser version and updated the goldens to match the iframe changed
   introduced in PR#13045.

sdks/python/apache_beam/runners/interactive/testing/integration/screen_diff.py

@@ -75,25 +75,22 @@ def __init__(self, test_notebook_path, golden_dir, cleanup=True):
     self._cleanup = cleanup
     self._test_urls = {}
     self._server = None
-    self._server_daemon = None
 
   def __enter__(self):
     self._notebook_executor.execute()
-    with HTTPServer(('', 0), SimpleHTTPRequestHandler) as server:
-      self._server = server
+    self._server = HTTPServer(('', 0), SimpleHTTPRequestHandler)
 
-      def start_serving(server):
-        server.serve_forever()
+    def start_serving(server):
+      server.serve_forever()
 
-      self._server_daemon = Process(
-          target=start_serving, args=[server], daemon=True)
-      self._server_daemon.start()
+    threading.Thread(
+        target=start_serving, args=[self._server], daemon=True).start()
 
-      for test_id, output_path in\
-        self._notebook_executor.output_html_paths.items():
-        self._test_urls[test_id] = self.base_url + output_path
+    for test_id, output_path in\
+      self._notebook_executor.output_html_paths.items():
+      self._test_urls[test_id] = self.base_url + output_path
 
-      return self
+    return self
 
   def __exit__(self, exc_type, exc_value, traceback):
     if self._notebook_executor and self._cleanup:
@@ -105,8 +102,6 @@ def stop_serving(server):
 
       threading.Thread(
           target=stop_serving, args=[self._server], daemon=True).start()
-    if self._server_daemon:
-      self._server_daemon.terminate()
 
   @property
   def base_url(self):

sdks/python/setup.py

@@ -234,7 +234,7 @@ def get_version():
     # headless chrome based integration tests
     'selenium>=3.141.0,<4',
     'needle>=0.5.0,<1',
-    'chromedriver-binary>=83,<84',
+    'chromedriver-binary>=85,<86',
     # use a fixed major version of PIL for different python versions
     'pillow>=7.1.1,<8',
 ]