Add GitHub Actions workflow to test tools (#54207)

Summary:
This PR closes https://github.com/pytorch/pytorch/issues/52866 by adding a GitHub Actions workflow to run the tests in the dir introduced by https://github.com/pytorch/pytorch/issues/53755. It also uses `actions/setup-python@v2`, assuming that https://github.com/pytorch/pytorch/issues/54202 will be merged.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/54207

Test Plan: The added "Test tools" GHA workflow in CI.

Reviewed By: walterddr

Differential Revision: D27135159

Pulled By: samestep

fbshipit-source-id: c8c5e2e2ac2491baab1b1f1ed4f44b4c3266ee8d
diff --git a/.github/workflows/test_tools.yml b/.github/workflows/test_tools.yml
new file mode 100644
index 0000000..0ae159a
--- /dev/null
+++ b/.github/workflows/test_tools.yml
@@ -0,0 +1,25 @@
+name: Test tools
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-18.04
+    steps:
+      - name: Setup Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.x
+          architecture: x64
+      - name: Checkout PyTorch
+        uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+      - name: Install dependencies
+        run: pip install -r requirements.txt
+      - name: Run tests
+        run: python -m unittest discover -vs tools/test -p 'test_*.py'