[flutter_releases] beta 3.23 release engine - actually delete impeller tests (#53178)

This is a follow up to #53163, where I deleted the ninja target to build the golden tests, however I forgot to delete the commands to actually run the tests. In post-submit, the tests ran again and failed: https://ci.chromium.org/ui/p/dart-internal/builders/flutter/Mac%20Production%20Engine%20Drone/12733/infra

This PR actually deletes the scripts to run the tests.

Author: christopherfujino

ci/builders/mac_host_engine.json

@@ -464,20 +464,7 @@
                 "$flutter/osx_sdk": {
                     "sdk_version": "15a240d"
                 }
-            },
-            "tests": [
-                {
-                    "language": "python3",
-                    "name": "Impeller-golden for host_release",
-                    "script": "flutter/testing/run_tests.py",
-                    "parameters": [
-                        "--variant",
-                        "ci/mac_release_arm64",
-                        "--type",
-                        "impeller-golden"
-                    ]
-                }
-            ]
+            }
         }
     ],
     "generators": {