TEST-#1876: Add tests running under experimental

Signed-off-by: Vasilij Litvinov <vasilij.n.litvinov@intel.com>

.github/workflows/ci.yml

@@ -128,6 +128,27 @@ jobs:
       - run: python -m pytest modin/experimental/pandas/test/test_io_exp.py
         if: matrix.part == 3
       - run: bash <(curl -s https://codecov.io/bash)
+  test-experimental:
+    needs: [lint-commit, lint-flake8, lint-black, test-api, test-headers]
+    runs-on: ubuntu-latest
+    env:
+      MODIN_ENGINE: "python"
+      MODIN_EXPERIMENTAL: "True"
+      MODIN_MEMORY: 1000000000
+    name: test experimental
+    steps:
+      - uses: actions/checkout@v1
+        with:
+          fetch-depth: 1
+      - uses: actions/setup-python@v1
+        with:
+          python-version: "3.7.x"
+          architecture: "x64"
+      - run: pip install -r requirements.txt
+      - run: python -m pytest modin/pandas/test/test_dataframe.py::TestDataFrameMapMetadata
+      - run: python -m pytest modin/pandas/test/test_series.py
+      - run: python -m pytest modin/pandas/test/test_io.py
+      - run: bash <(curl -s https://codecov.io/bash)
   test-windows:
     needs: [lint-commit, lint-flake8, lint-black, test-api, test-headers]
     runs-on: windows-latest