Add option to skip certain unit tests

Differential Revision: D72815908

Author: aporialiao

.github/scripts/tests_to_skip.txt

@@ -0,0 +1 @@
+test_sharding_fused_ebc_as_top_level

.github/workflows/unittest_ci_cpu.yml

@@ -72,6 +72,8 @@ jobs:
           python -c "import numpy"
         echo "numpy succeeded"
         conda install -n build_binary -y pytest
+        skip_expression=$(awk '{printf " and not %s", $0}' ./.github/scripts/tests_to_skip.txt)
+        skip_expression=${skip_expression:5}  # Remove the leading " and "
         conda run -n build_binary \
           python -m pytest torchrec -v -s -W ignore::pytest.PytestCollectionWarning --continue-on-collection-errors \
-          --ignore-glob=**/test_utils/
+          --ignore-glob=**/test_utils/ -k "$skip_expression"