Enable tests/strings/test_api.py and tests/io/pytables in cudf.pandas…

… tests (#15461)

closes #15425
closes #15427

The `tests/io/pytables` tests are technically skipped since they are marked `single_cpu` and we run `-m not single_cpu`

Authors:
  - Matthew Roeschke (https://github.com/mroeschke)
  - GALI PREM SAGAR (https://github.com/galipremsagar)

Approvers:
  - Vyas Ramasubramani (https://github.com/vyasr)
  - GALI PREM SAGAR (https://github.com/galipremsagar)

URL: #15461

python/cudf/cudf/pandas/scripts/run-pandas-tests.sh

@@ -24,10 +24,8 @@ PANDAS_VERSION=$(python -c "import pandas; print(pandas.__version__)")
 
 PYTEST_IGNORES="--ignore=tests/interchange/test_impl.py \
 --ignore=tests/window/test_dtypes.py \
---ignore=tests/strings/test_api.py \
 --ignore=tests/window/test_numba.py \
 --ignore=tests/window \
---ignore=tests/io/pytables \
 --ignore=tests/plotting \
 --ignore=tests/scalar \
 --ignore=tests/series/test_arithmetic.py \