CI: tolerate runner mtime lag and stream heartbeat race in 2 browser tests (test-only, no production code change; playwright: 0.05s sleep after write_control, runner mtime lags wall clock 0.2-1.0ms; stream: drain waiting heartbeats until EOF after terminal status)

cloud/tests/test_server_browser_proxy.py

@@ -214,7 +214,19 @@ class BrowserProxyTestCase(unittest.TestCase):
                 db.commit()
             finally:
                 db.close()
-            line = resp.readline().decode("utf-8")
+            # Terminal status ends the stream, but a waiting
+            # heartbeat may fire first on a loaded runner; drain
+            # waiting frames until EOF instead of requiring the
+            # first line after the update to be EOF.
+            for _ in range(20):
+                line = resp.readline().decode("utf-8")
+                if line == "":
+                    break
+                if line.strip() == "":
+                    continue
+                payload = json.loads(line[6:]) if line.startswith("data: ") else {}
+                if not payload.get("waiting"):
+                    break
             self.assertEqual(line, "")
         finally:
             conn.close()