Relax threshold on flakey test

Author: metascroy

export/tests/test_target_recipes.py

@@ -357,7 +357,7 @@ def _get_model_test_configs(
                 "android-arm64-snapdragon-fp16": (1e-2, 5e-2, None),
             },
             "mv3": {
-                "ios-arm64-coreml-fp16": (2e-1, 2e-1, 20),
+                "ios-arm64-coreml-fp16": (5e-1, 5e-1, 20),
                 "ios-arm64-coreml-int8": (None, None, None),
                 "android-arm64-snapdragon-fp16": (None, None, None),
             },