add linux-aarch64 to circleci tests

.circleci/config.yml

@@ -37,9 +37,30 @@ jobs:
           command: venv/bin/python ./bin/run_tests.py
           no_output_timeout: 30m
 
+  linux-aarch64:
+    machine:
+       image: ubuntu-2004:2022.04.1
+    resource_class: arm.medium
+    environment:
+      PYTHON: python3
+      # Temporarily restrict the tests that are run on CircleCI to prevent
+      # test timeouts.
+      PYTEST_ADDOPTS: -k "unit_test or main_tests or test_0_basic or test_docker_images"
+    steps:
+      - checkout
+
+      - run:
+          name: Prepare the environment.
+          command: bash .circleci/prepare.sh
+      - run:
+          name: Test.
+          command: venv/bin/python ./bin/run_tests.py
+          no_output_timeout: 30m
+
 workflows:
   version: 2
   all-tests:
     jobs:
       - osx-python3.9
       - linux-python3.9
+      - linux-aarch64